At HackerRank, we’ve always believed in the power of skills over pedigree. HackerRank Community (HRC) is our way of putting that belief into practice. It’s where millions of developers sharpen their skills, tackle real-world problems, and find their way into careers that matter.

HackerRank helps you level up, whether you’re new to coding or a seasoned professional.

Learn by doing

Practice by solving real problems. You’ll find thousands of coding challenges across many topics like algorithms, data structures, databases, AI and more. It’s not about cramming for a test or following tutorials you’ll forget tomorrow. It’s about building muscle memory through practice.

Every problem you solve adds to your skill portfolio, and you can see that progress in real-time. With every badge earned, your skill set becomes clearer adding layers to your coding story.

Skill tracks that work for you

No one learns in the same way, so we give you flexible learning paths through skill tracks. Each track is a guided path that keeps you focused on the right topics, but you move at your own pace. Want to dig deeper into algorithms? Great. Want to switch over to Python for a while? No problem.

What really matters is that you stay in control of your learning experience, and by the time you finish a track, you get a badge and certificate that is an industry standard.

Get ready for real interviews

Developers know coding well is one thing, but nailing the interview? That’s a different game. HackerRank now helps you prepare for that with AI-powered mock interviews (currently in limited access). That simulates real interview scenarios, giving you a chance to practice before it counts.

Think of it as a practice session before a big interview. You’ll get feedback on what you did well and where you can improve, so by the time you’re in front of a real interviewer, you’re ready to go.

Interested in accessing our new mock interview feature? Get in touch with our team.

From coding to career

We know coding skills aren’t the only thing that matters when you’re job hunting. HackerRank goes beyond the code. We’ve got tools, like a resume builder and a Chrome Extension to automatically fill up job application forms, to make sure you’re presenting yourself the right way, and job matching to help you connect with opportunities that match your skills.

Go beyond just theory and focus on taking your career from learning to landing the right job. When you’re ready to showcase your skills, certifications provide the proof you need, backed by credentials that hiring managers trust.

A global community to learn and compete 

One of the best things about Community is that you’re never learning alone. Connect yourself to one of the largest developer communities in the world. The discussion forums are packed with ideas, insights, and real solutions from people who’ve been there before.

And if you’re feeling competitive, dive into challenges to prove yourself through coding competitions and hackathons. These aren’t just for fun (though they are). They’re a chance to rise through the ranks, get noticed, and see how you stack up against the best.

Skills over Pedigree

It’s not about what school you went to or what your resume says, it’s about what you can actually do. And we’ve built HackerRank to help you prove that to the world.

Whether you’re just starting out or looking to refine your skills, the HackerRank community is here to support you at every step. From problem-solving practice to job prep, it’s the place to grow as a developer.

The post Upgrades to the HackerRank Community appeared first on HackerRank Blog.

Transitioning from an individual contributor to a managerial role is one of the most significant shifts a software developer can make. While technical skills remain important, becoming an engineering manager requires a different set of capabilities—leadership, communication, and strategic planning. This transition can be challenging, but with the right preparation and mindset, it’s a highly rewarding step in a developer’s career.

Understanding the Shift in Responsibilities

When you were a developer, your focus was coding, problem-solving, and delivering solutions. As an engineering manager, your primary responsibilities now shift towards guiding teams, developing talent, and ensuring the alignment of engineering goals with company objectives.

In this new role, you’ll need to let go of the hands-on tasks that once defined your daily work. The focus moves to managing the people who execute the technical work and empowering them to succeed.

Your new day-to-day activities include running meetings, setting goals, coordinating projects, and addressing challenges related to team dynamics. According to a study by Gallup, managers being actively involved in team development lead to a 59% reduction in turnover. This emphasizes the critical nature of leadership in retaining top talent.

Building New Skills for Management

As you transition into management, you must cultivate new skills to complement your technical background. These include communication, conflict resolution, time management, and strategic planning. But most importantly, you’ll need to focus on leadership.

Leadership and Communication

Leadership in engineering isn’t just about making decisions—it’s about guiding a team through challenges and setting a clear direction. Communication breakdowns or a lack of communication skills are believed to contribute to 86% of workplace failures. 

Engineering teams rely heavily on collaboration across different functions—developers, product managers, designers, and QA teams must work in sync. A coding team leader with strong communication skills can prevent bottlenecks, align team efforts toward common objectives, and provide timely feedback, which fosters continuous improvement. 

Time Management

Balancing competing priorities is another critical skill. While you may still want to code occasionally, you must allocate time efficiently across managerial duties like performance reviews, one-on-ones, and project oversight. Adopting frameworks like the Eisenhower Matrix can help you distinguish between urgent and important tasks, keeping you focused on what matters most.

Assessing Technical Skills

With the move to engineering management comes another responsibility: building your team. 

In tech organizations, hiring the right talent is critical for project success and innovation. By developing the ability to evaluate technical competencies and soft skills, managers can ensure that candidates not only meet the technical demands of the role but also align with the team’s culture and values. To do this, managers should focus on structured interview processes, use technical assessments such as coding challenges, and involve team members in the evaluation process. Learning to assess candidates holistically enables engineering managers to make informed decisions, leading to better hires and a more cohesive, productive team.

Overcoming Common Challenges

Transitioning into management comes with inevitable challenges. According to research by Harvard Business Review, 60% of new managers fail within their first two years due to inadequate preparation. Consider preparing for these two common challenges and learning how to overcome them.

Letting Go of the Code

One of the most common challenges for developers moving into management is letting go of coding. Many developers struggle with not being directly involved in day-to-day technical tasks. While it’s tempting to dive back into code to solve a problem or fix a bug, it’s important to remember that your focus should now be guiding your team and enabling them to solve these challenges.

Handling Conflict and Team Dynamics

Another common challenge is managing conflict and maintaining team morale. Engineering teams often have diverse personalities and skill sets, which can lead to tension. Managers must constructively mediate conflicts, ensuring issues are resolved without disrupting productivity. Effective conflict resolution helps maintain a positive work environment and contributes to a more cohesive and collaborative team.

Balancing Technical and Managerial Tasks

In your new role, you’ll often feel pulled between technical tasks and managerial responsibilities. Striking the right balance is key to your success as an engineering manager.

Delegation

One of the most powerful tools for a manager is delegation. While you may have been the go-to person for solving technical challenges, it’s now your job to empower your team to solve these issues themselves. Delegating tasks frees up your time for more strategic duties and fosters team growth and ownership.

Staying Technically Proficient

At the same time, staying current with industry trends and technologies is important. Engineering managers must know emerging tools and methodologies to ensure their team works efficiently. Set aside time for technical learning, whether it’s through attending conferences, reading industry blogs, or engaging in periodic coding tasks.

Tips for a Successful Transition

1. Find a Mentor: Seek an experienced engineering manager to guide you through the transition. Having someone to turn to for advice on leadership challenges can be incredibly valuable.
2. Set Clear Expectations: Make sure your team understands your role and responsibilities. Clarify that while you may not be coding as much, you are there to support their technical development and ensure the team’s success.
3. Stay Organized: Use project management tools to manage both your managerial and technical tasks. Staying organized will help you balance your time more effectively and ensure nothing slips through the cracks.
4. Emphasize Team Development: Encourage team members to take on challenges and grow. Providing opportunities for skill development and career growth is one of the best ways to keep your team engaged and productive.

Conclusion: Embracing the New Role

Transitioning from developer to engineering manager is a rewarding yet demanding journey. You can become a successful and effective manager by developing new leadership skills, maintaining technical proficiency, and fostering a positive team environment. Remember, the goal is to lead and empower your team to succeed and grow, setting the team and the company up for long-term success.

The post Engineering Leadership: Transitioning from Developer to Manager appeared first on HackerRank Blog.

Building a high-performing engineering team is more than just assembling a group of talented developers; it requires strategic planning, effective management, and a commitment to continuous skill growth. 

This article provides practical insights and best practices to help managers cultivate and maintain a high-performing engineering team. 

Define a High-Performing Engineering Team

A high-performing engineering team consistently delivers high-quality work, meets deadlines, and continuously innovates. These teams are characterized by strong collaboration, clear communication, and a shared sense of purpose. They are agile, adaptable, and committed to achieving the organization’s goals.

But what sets a high-performing team apart? According to Google’s Project Aristotle, the most successful teams are not just a mix of the brightest minds but are built on psychological safety, dependability, structure, clarity, meaning, and impact. These teams are skilled and cohesive, with members who feel valued and empowered to contribute their best.

Hire the Right Talent

The foundation of a high-performing team begins with hiring the right talent. The goal is to find candidates who have the necessary technical skills and fit well with the team’s culture and values.

To best assess a candidate’s technical abilities, consider using coding tests that reflect real-world challenges they would face on the job. This approach provides a stronger signal of a developer’s skills than algorithm-style or trivia-based questions.

Platforms like HackerRank offer tools for creating customized coding assessments that measure a candidate’s proficiency in specific languages, frameworks, and problem-solving skills.

Beyond coding tests, the interview process should also evaluate soft skills, such as communication, teamwork, and adaptability. Use a structured interview format to ensure consistency and fairness, and consider involving team members in the interview process to gauge cultural fit.

Establish Clear Goals and Expectations

Once you’ve built your team, it’s crucial to establish clear goals and expectations from the outset. High-performing teams thrive when they understand what’s expected of them and how their work contributes to the larger organizational goals.

Setting SMART Goals: Use the SMART criteria (Specific, Measurable, Achievable, Relevant, Time-bound) to set clear objectives for your team. This helps in tracking progress and ensures that each team member knows what they’re working towards.

Regular Check-Ins and Feedback: Regular one-on-one meetings and team check-ins are essential for maintaining alignment and addressing issues before they become major roadblocks. These meetings should be a two-way conversation where team members feel comfortable sharing their progress and any challenges they face.

How to Do This:

• Develop SMART goals that align with the overall objectives of the organization.
• Hold regular check-ins to monitor progress and provide constructive feedback.
• Use project management tools like Jira to track goals and milestones.

Investing in Continuous Learning and Development

The tech industry is constantly evolving, and continuous learning and development are essential to keeping your team at the forefront. High-performing teams never stop learning.

Provide Access to Learning Resources: Give your team access to the latest learning resources, such as online courses, webinars, and workshops. Platforms like Coursera and Udemy offer various courses tailored to software engineers and developers.

Encourage Knowledge Sharing: Foster a culture where team members are encouraged to share their knowledge. This could be through regular “lunch and learn” sessions, internal wikis, or informal coding meetups.

How to Do This:

• Allocate budget and time for continuous learning and development programs.
• Encourage team members to take courses on platforms like Coursera or Udemy.
• Promote internal knowledge sharing through regular learning sessions or an internal knowledge base.

Encourage Ownership and Accountability

High-performing teams take ownership of their work and are accountable for their outcomes. This sense of ownership drives quality and fosters a culture of responsibility.

Delegate Responsibility: Empower your team by delegating responsibilities and giving them the autonomy to make decisions. This not only boosts morale but also helps develop team leadership skills.

Foster a Blame-Free Culture: Encourage a culture where mistakes are seen as learning opportunities rather than reasons for blame. This approach helps build trust and encourages team members to take risks and innovate.

How to Do This:

• Delegate tasks and responsibilities to team members based on their strengths.
• Establish a culture where accountability is expected, but blame is avoided.
• Use retrospectives after project completion to discuss what went well and what can be improved without assigning blame.

Measure and Improving Team Performance

Regularly evaluating your team’s performance is essential to ensure your team remains high-performing.

Use Performance Metrics: Set clear performance metrics to track both individual and team progress. Here are some key metrics to pay attention to:

• Deployment Frequency: This measures how often your team is able to deploy new code to production. Tools like CircleCI can help track this metric by providing insights into your CI/CD pipeline.
• Code Review Turnaround Time: Track the average time it takes for code reviews to be completed. You can use platforms like Phabricator or the code review features in GitHub and GitLab to monitor this.
• Cycle Time: Cycle time measures the time taken from starting work on a feature to its delivery in production. Tools like JIRA and Azure DevOps can help you track cycle time and identify bottlenecks in your development process.
• Team Morale: Although harder to quantify, regular surveys using tools like Officevibe or Culture Amp can provide insights into team satisfaction and areas for improvement. 

Continuous Feedback Loop: Implement a continuous feedback loop where performance data is regularly reviewed and feedback is given. This helps identify areas for improvement and ensures that the team is always moving forward.

How to Do This:

• Identify key performance metrics that align with your team’s goals.
• Use tools like GitHub and Jenkins to monitor performance metrics.
• Conduct regular performance reviews and provide actionable feedback.

Conclusion

Building a high-performing engineering team is an ongoing process that requires careful planning, continuous investment in learning, and a strong focus on team dynamics. By following these best practices—hiring the right talent, setting clear goals, fostering a culture of continuous learning, encouraging ownership, and regularly measuring performance—you can build a team that meets and exceeds expectations, driving innovation and success for your organization.

The post Building High-Performing Engineering Teams: Best Practices for Managers appeared first on HackerRank Blog.

Fostering a mentorship culture has become essential for organizations aiming to attract, develop, and retain top talent. Mentorship programs help bridge the skill gap and create a supportive environment where employees thrive. 

Increasingly, companies and tech teams are recognizing the profound impact these initiatives have on individual and organizational success.

In this article we cover why mentorship is a must for tech companies and the best practices to build a successful mentorship program. 

Why Mentorship Matters in Tech

Mentorship has become a cornerstone of professional development for tech teams. According to a 2024 study by MentorcliQ, 98% of U.S. Fortune 500 companies have established mentoring programs, with 100% of the top 50 U.S. Fortune 500 companies adopting these initiatives. This significant shift reflects a broader trend: the increasing recognition of mentorship as a critical tool for fostering technical skills, employee growth, and a strong engineering culture.

Mentorship programs offer numerous benefits, including:

• High ROI on Learning and Development (L&D) Programs: Effective mentorship programs are instrumental in building core competencies, such as technical skills, emotional intelligence, communication, and negotiation. These programs ensure that employees are continuously learning and adapting to new challenges, which is crucial in the fast-paced tech industry.
• Enhanced Internal Relationships: Mentorship fosters stronger relationships within the organization, creating a sense of belonging that can lead to higher employee retention and improved workplace morale. This sense of community is particularly important in tech, where teamwork and collaboration are key to success.
• Confidence and Career Development: Mentees often experience increased confidence, leading to lower levels of anxiety and more streamlined career progression. Mentors, too, benefit from these relationships by honing their leadership skills and gaining fresh perspectives from their mentees.
• Positive Impact on the Bottom Line: Research has shown that companies with mentorship programs tend to outperform those without. According to Forbes, companies with mentoring programs saw profits that were 18% better than average, while those without such programs had profits that were 45% worse than average. 

Types of Mentorship Relationships

Mentorship relationships in the tech industry can take various forms, each catering to different needs and organizational goals. Here are some common types of mentorship relationships to consider:

1. Traditional Mentorship

In this model, a seasoned professional partners with a less experienced colleague to provide resources, offer connections, and help them build competencies. Traditional mentorship often focuses on career progression and leadership development. However, mentors also benefit from reverse mentoring, gaining insights into current trends and innovations from their mentees.

2. Peer-to-Peer Mentorship

This form of mentorship occurs between individuals at similar career stages. It builds connections and fosters a sense of community within the organization or across the industry. Peer-to-peer mentorship is particularly valuable for enhancing team effectiveness and developing a collaborative culture.

3. Group Mentorship

In this model, a single mentor or a group of mentors is paired with several mentees. This approach is cost-effective and promotes knowledge sharing within the organization. It’s especially useful when there’s a shortage of mentors or when mentees prefer learning in a group setting.

4. Onboarding Mentorship

New hires are paired with internal company mentors who help them understand the organization’s culture, values, goals, and team dynamics. Onboarding mentorship can significantly improve new employees’ sense of belonging and job satisfaction, leading to quicker integration and higher retention rates.

5. Virtual Mentorship

With the rise of remote work, virtual mentorship has become more prevalent. This approach removes geographic barriers, allowing employees from different locations to connect and collaborate. Virtual mentorship is also aligned with diversity, equity, and inclusion (DEI) goals, providing equitable access to mentoring opportunities regardless of location.

Best Practices for Building a Mentorship Culture

Creating a successful mentorship program in tech requires careful planning and clear communication. Here are some best practices to ensure your program’s effectiveness:

#1. Set Clear Goals and Expectations

Mentors and mentees should clearly understand what they hope to achieve through the mentorship relationship. Define specific outcomes, such as skill-building, career development, or networking, and establish a plan for meeting these goals. This clarity will prevent misunderstandings and ensure that both parties are aligned in their expectations.

#2. Find the Right Match

Matching mentors and mentees is critical to a successful mentorship program. When pairing a mentee with a mentor, consider not only the mentee’s desired skill set and career goals but also the mentor’s expertise and willingness to share knowledge and connections. Equally important is ensuring that both parties have compatible communication skills and styles, as this can significantly impact the effectiveness of their collaboration.

#3. Establish a Structured Program

A well-structured mentorship program includes defined timelines, meeting frequencies, and formats. For example, pairs might agree to meet monthly for one-hour virtual or in-person sessions. Establishing these parameters upfront allows both parties to focus on the content of their discussions rather than logistics.

#4. Encourage Regular Feedback

Regular check-ins and feedback sessions are essential for the ongoing success of the mentorship relationship. Encourage mentors and mentees to discuss what’s working well and what could be improved. This continuous feedback loop will help address any issues early on and ensure the relationship remains productive.

#5. Educate and Support Mentors

Mentoring requires a specific set of skills, including active listening, empathy, and the ability to provide constructive feedback. Offer training and resources to help mentors develop these skills and remind them that their role is to guide, not to dictate. Encouraging mentors to recognize their knowledge’s limits and connect mentees with other resources when necessary will enhance the overall mentorship experience.

#6. Promote Psychological Safety

Creating an environment of trust and psychological safety is crucial for effective mentorship. Both mentors and mentees should feel comfortable discussing challenges, asking questions, and expressing concerns without fear of judgment. Establishing guidelines for communication and conflict resolution will help maintain this safe space.

The post Building a Mentorship Culture in Tech: Benefits and Best Practices appeared first on HackerRank Blog.

Career pathing is more than just a human resources buzzword; it’s a strategic approach to employee development that aligns personal ambitions with organizational goals.

For organizations, structured career paths attract top talent and improve retention by offering clear advancement opportunities. For employees, these paths provide a roadmap for professional growth, enhancing job satisfaction and engagement.

So how can you establish solid career paths that benefit the company and employees? This article will cover the benefits of career pathing and provide actionable steps to build effective career trajectories for your tech employees.

Benefits of Establishing Career Paths

For Companies

Attracting Top Talent

In a LinkedIn survey, 59% of tech talent listed career growth opportunities as the top reason they accepted a new role. Companies that showcase clear career advancement opportunities will be better able to attract potential hires to their workforce.

Increasing Retention

Career pathing helps employees visualize their future within the organization, leading to higher job satisfaction and retention. Companies that actively upskill employees reduce turnover and replacement costs. A LinkedIn study revealed that 94% of employees would stay at a company longer if it invested in their career development. On the flip side, employees who feel their organization has no opportunities for career growth are 12 times more likely to leave.

Improving Business Performance

Structured career paths motivate employees to perform better, leading to significant business benefits. Gallup found that highly engaged teams experience 81% less absenteeism, 18%-43% less turnover, and 23% higher profitability. Employees at tech companies that innovate and grow rapidly are more likely to stay with the company.

For Employees

Professional Growth

Clear career paths provide employees with a professional development roadmap, allowing them to acquire new skills and advance in their careers. According to a report by Deloitte, 71% of millennials expect their employers to provide opportunities for them to develop their skills and move forward in their careers.

Job Satisfaction

Employees feel more valued and engaged when they see opportunities for growth and development within their organization. A survey by the Work Institute found that lack of career development was the primary reason for voluntary turnover, with 22% of employees leaving their jobs for this reason.

Skill Development

Career pathing encourages continuous learning and skill acquisition, making employees more proficient and versatile. A study by the World Economic Forum found that by 2025, 50% of all employees will need reskilling due to changes in job requirements. Providing structured career paths helps employees keep up with these changes, ensuring they remain competitive and valuable within the organization.

Career Stability

Career paths offer employees a sense of stability and direction in their professional lives by providing a clear trajectory. This stability is essential in today’s volatile job market, as it reassures employees that they have a future within the organization. The same Deloitte report indicated that employees who feel their jobs are secure are 42% more engaged and 36% more productive. 

 How to Build Career Paths

1. Assess Your Business Needs

Building career paths starts with evaluating your business’s current and future skill needs. To identify key skill areas to build career paths around, you should:

• Identify critical roles, succession plans, and emerging job functions. 
• Create detailed job descriptions for these roles, including the required skills, qualifications, and experience. 
• Assess departments and teams to identify skill gaps within your organization. This essential step ensures that your career pathing aligns with organizational goals and proactively maintains crucial skills needed for growth.

2. Discuss Career Goals with Employees

Hold regular discussions with your team members to understand their career aspirations. Encourage open dialogue about their short- and long-term goals and identify the skills and future job opportunities each employee seeks. This personalized approach helps create tailored career paths that align with employee ambitions and business needs.

3. Build Career Pathways

Craft detailed career pathways that outline the skills, knowledge, and experience required for each role. Ensure these pathways are flexible, allowing for non-linear progression, as employees in tech often move laterally or across functions based on their interests and the company’s needs. This approach provides clarity and direction, empowering employees to visualize their career trajectories within the organization.

4. Create an Upskilling and Mobility Plan

An internal mobility strategy is a framework that facilitates the transition of employees between roles, departments, or locations within a company. Instead of looking outward when a position opens, companies first assess their internal talent pool. 

Continuous learning is crucial in the tech industry. Develop an upskilling plan that includes:

• On-the-Job Training: Encourage employees to take on new responsibilities and projects that challenge their skill sets.
• Online Courses and Certifications: Provide relevant courses and certifications using platforms like HackerRank, Coursera, and Udemy.
• Conferences, Webinars, and Workshops: Facilitate attendance at industry events to keep employees updated with the latest trends and innovations. These workshops can include sessions with department leaders, interactive activities, and personalized career planning.
• Mentoring and Coaching: Pair less experienced employees with seasoned mentors to foster knowledge transfer and professional growth.

5. Monitor and Evaluate Progress

Ensure that career pathways remain relevant and up-to-date by regularly reviewing and updating them based on industry trends, technological advancements, and organizational changes. 

Use upskilling tools, presentations, and project evaluations to measure skill improvements. Engage in two-way communication to provide and receive feedback, ensuring that the career pathing process remains dynamic and responsive to changing needs. This keeps the career development process dynamic and aligned with the evolving needs of the business.

6. Reward and Recognize Growth

Acknowledge and reward employees’ progress along their career paths. This can be through promotions, pay increases, or public recognition. Celebrating achievements boosts morale and motivation, reinforcing a culture of continuous development. 

Career pathing is a continuous and evolving process, much like the tech field itself. Regularly revisit and refine your strategies to ensure they remain relevant and effective, driving success for your employees and your business.

The post How to Establish Career Paths for Your Tech Employees appeared first on HackerRank Blog.

When it comes to succeeding in tech, staying current is not just an advantage—it’s a necessity. New algorithms, programming languages, and tools emerge constantly. Upskilling your software engineering team is essential for maintaining a competitive edge and ensuring your company remains at the forefront of innovation. In this article, we’ll break down how tech companies and engineering managers can identify the skills their software engineering teams need and develop an effective upskilling strategy.

Why You Should Upskill Your Software Engineering Team

The U.S. Bureau of Labor estimates job opportunities for software developers, quality assurance analysts, and testers will grow by 25% between now and 2032. Over 153,000  jobs are projected yearly due to workers retiring or entering a different industry. To put this into perspective, the average projected growth across all occupations during that same time is only 2.8%. 

This rapid growth means that, in the long term, companies are likely to face significant challenges in finding the engineering skills they need. Additionally, existing teams will need to continuously learn new skills to keep up with the pace of innovation.

Upskilling is an increasingly attractive solution for closing these skills gaps and realizing a range of compelling benefits.

1. Enhanced Productivity and Efficiency

Upskilled employees can leverage new tools and technologies to streamline workflows and automate repetitive tasks, thereby increasing productivity. And continuous learning enhances problem-solving abilities, enabling employees to tackle challenges more efficiently and reduce downtime. This focus on complex, value-adding activities can significantly boost operational efficiency.

2. Improved Employee Retention and Reduced Turnover

Developers recognize the importance of learning new skills and staying relevant. According to LinkedIn, 94% of employees would stay at a company longer if it invested in their career development. 

High turnover rates are costly, with productivity losses estimated to cost 30% to 200% of an employee’s annual income. Then there is the cost of replacing an employee, roughly equivalent to nine months of their salary. Upskilling helps companies avoid these costs while improving efficiency and innovation. 

3. Competitive Advantages

As technology evolves, specific skills become obsolete while new ones emerge. Continuously upskilling employees ensures they are prepared to handle upcoming technological shifts and challenges. This proactive approach positions companies at the forefront of industry changes.

By upskilling, companies bridge the skills gap, boost productivity, foster innovation, and retain valuable employees. This strategic approach ensures the company and its workforce are well-prepared for the future. Upskilling is not just a response to current challenges; it’s an investment in long-term success.

How to Identify Skills Gaps

Before you can effectively upskill your data science team, you need to identify your skills gaps. This involves both a high-level overview of your team’s capabilities and a deep dive into individual competencies.

Start by reviewing your current projects and pipelines. What are the common bottlenecks? Where do the most challenges or errors occur? Answers to these questions can shed light on areas that need improvement. 

Next, look at the individual members of your team. Everyone has their own unique set of strengths and weaknesses. Some may be fantastic with code reviews but could improve their communication skills. Others might be proficient in Python but not as adept with SQL. You can identify these individual skill gaps through regular performance reviews, one-on-one check-ins, or even anonymous surveys. 

Remember, the goal here is not to criticize or find fault but to identify opportunities for growth. The process of determining the skills gap should be collaborative and constructive and should empower team members to take ownership of their professional development.

Once you have a clear picture of the skills gaps in your team, you can start to strategize about the most effective ways to bridge these gaps. 

Upskilling Strategies

1. On-the-Job Training: Learning by doing is highly effective. Encourage your team to take on new responsibilities or projects that stretch their skills. Provide resources and support, but give them the autonomy to learn and grow.
2. Online Courses and Certifications: The internet is full of learning resources. Platforms like HackerRank, Coursera, and Udemy offer courses in various tech subjects. These courses often come with certifications that validate your team’s new skills.
3. Conferences, Webinars, and Workshops: These events offer opportunities to learn from industry experts and stay updated with the latest trends. Encourage your team to attend these events, either in person or virtually.
4. Mentoring and Coaching: Pairing less experienced team members with seasoned professionals can facilitate knowledge transfer. Mentors share their successes and mistakes, while mentees bring fresh perspectives.
5. Experiential Learning: This educational approach emphasizes learning through direct, hands-on experiences. For example, hackathons provide developers with practical, immersive learning opportunities.

Remember, different team members have different learning styles. Some may prefer structured online courses, while others thrive on practical application. Offer a mix of learning opportunities to accommodate these diverse preferences.

Measuring Success and Tracking Progress

How can you determine if your upskilling efforts are yielding results? Here are some key metrics to measure success: 

• Improvement in Project Outcomes: Look for better work quality and efficiency as team members apply new skills, such as faster turnaround times or higher-quality code.
• Increased Efficiency: Expect greater autonomy and efficiency within your team, including bringing previously outsourced tasks in-house and streamlining processes.
• Feedback from Team Members: Regularly gather insights from your team to assess the effectiveness of upskilling efforts and identify areas for improvement.
• Skill Assessments: Measure skill improvements through quizzes, presentations, or project-based evaluations conducted regularly.
• Retention Rates: Monitor turnover rates to gauge the success of upskilling initiatives. Employees are more likely to stay with a company that invests in their growth.

Utilize this feedback to fine-tune your program as required. Tracking progress aims to provide insights rather than impose pressure, helping you comprehend the team’s development. Celebrate achievements and perceive obstacles as chances to enhance your upskilling approach.

The post How to Upskill Your Software Engineering Team appeared first on HackerRank Blog.

APIs — or application programming interfaces — play a key role in the software ecosystem. In a tech world that hinges on its interconnectedness, APIs serve as the vital middlemen that enable different pieces of software to work together seamlessly. And in the realm of APIs, REST (Representational State Transfer) stands as one of the most popular architectures. Why? Because it’s simple, scalable, and can handle multiple types of calls, return different data formats, and even change structurally with the correct implementation of hypermedia.

Given the ubiquitous role of REST APIs in modern software development, it’s not an overstatement to say that strong REST API skills are a must-have for developers across various disciplines — from full-stack and back-end developers to data scientists. But let’s not forget the recruiters and hiring managers striving to find the best talent. Knowing what questions to ask and what tasks to set during a technical interview can make a world of difference in finding the right hire.

In this blog post, we’re going to delve into what a REST API is, look at what you can expect from a REST API interview, and provide some challenging coding questions aimed at testing a developer’s REST API expertise. Whether you’re a developer looking to prepare for your next interview or a recruiter aiming to assess candidates proficiently, this post aims to be your go-to guide.

What is a REST API?

REST, short for representational state transfer, is an architectural style that sets the standard for creating web services. A REST API, therefore, is a set of conventions and rules for building and interacting with those services. 

The key components that define this architectural style include:

• Resources: In REST, you interact with resources, which are essentially objects like users, products, or orders, represented as URLs or endpoints.
• HTTP Methods: These resources are manipulated using standard HTTP methods. You’ve got GET for reading, POST for creating, PUT for updating, and DELETE for, well, deleting.
• Stateless Interactions: REST APIs operate on a stateless basis. Every API request from a client to a server must contain all the information needed to process the request. This is one of the reasons why REST APIs are so scalable.

Simplicity, scalability, and versatility are hallmarks of REST APIs — and are some of the key reasons why this API protocol is so popular. REST APIs employ straightforward HTTP methods, are built to scale, and can return data in various formats (most commonly JSON and XML). With such attributes, plus strong community and library support, REST APIs have become the crucial connective tissue linking different services, applications, and systems in an increasingly integrated tech world.

What a REST API Interview Looks Like

When you’re sitting down for a REST API interview — either as a candidate eager to showcase your skills or as a member of a hiring team aiming to discover top talent — know that the focus will go beyond basic programming. You’ll explore the depths of HTTP methods, status codes, API endpoints, and the intricacies of data manipulation and retrieval. Understanding REST isn’t just about knowing the syntax; it’s about grasping the architecture, the philosophy, and the best practices that guide efficient API design and usage.

In this context, you may be asked to handle a variety of challenges:

• Conceptual discussions about REST principles to gauge your foundational knowledge.
• Hands-on coding tasks that require you to implement specific API calls, perhaps even integrating third-party services.
• Debugging exercises where you’re given pieces of a RESTful service and asked to identify issues or optimize performance.
• Scenarios where you have to design RESTful routes and resources, showcasing your understanding of RESTful best practices.

So who needs to be proficient in REST APIs? Well, you’d be hard-pressed to find a technical role that doesn’t benefit from REST API skills. However, they’re particularly essential for:

• Back-End Developers: The architects behind the server-side logic, often responsible for setting up the API endpoints.
• Full-Stack Developers: The jacks-of-all-trades who need to know both client-side and server-side technologies, including APIs.
• API Developers: Those specializing in API development, obviously.
• Data Scientists and Engineers: Professionals who need to pull in data from various services for analytics and data processing.
• Mobile App Developers: Many mobile apps pull from web services, often using REST APIs.
• QA Engineers: Those responsible for testing the reliability and scalability of web services, including APIs.

1. Create a Simple RESTful Service to Manage a To-Do List

This question serves as a foundational task to assess your grasp of REST API basics, CRUD operations, and endpoint creation.

Task: Write a Python function using the Flask framework to manage a simple to-do list. Your API should support the following operations: adding a new task, getting a list of all tasks, updating a task description, and deleting a task.

Input Format: For adding a new task, the input should be a JSON object like `{“task”: “Buy groceries”}`.

Constraints:

• The task description will be a non-empty string.
• Each task will have a unique identifier.

Output Format: The output should also be in JSON format. For fetching all tasks, the output should look like `[{“id”: 1, “task”: “Buy groceries”}, {“id”: 2, “task”: “Read a book”}]`.

Sample Code:

from flask import Flask, jsonify, request

app = Flask(__name__)

tasks = []

task_id = 1

@app.route('/tasks', methods=['GET'])

def get_tasks():

    return jsonify(tasks)

@app.route('/tasks', methods=['POST'])

def add_task():

    global task_id

    new_task = {"id": task_id, "task": request.json['task']}

    tasks.append(new_task)

    task_id += 1

    return jsonify(new_task), 201

@app.route('/tasks/<int:id>', methods=['PUT'])

def update_task(id):

    task = next((item for item in tasks if item['id'] == id), None)

    if task is None:

        return jsonify({"error": "Task not found"}), 404

    task['task'] = request.json['task']

    return jsonify(task)

@app.route('/tasks/<int:id>', methods=['DELETE'])

def delete_task(id):

    global tasks

    tasks = [task for task in tasks if task['id'] != id]

    return jsonify({"result": "Task deleted"})

Explanation:  

The Python code uses Flask to set up a simple RESTful API. It has four endpoints corresponding to CRUD operations for managing tasks. `GET` fetches all tasks, `POST` adds a new task, `PUT` updates a task based on its ID, and `DELETE` removes a task by its ID.

2. Implement Pagination in a REST API

This question is designed to gauge your understanding of pagination, a technique often used in REST APIs to manage large sets of data.

Task: Modify the previous Python Flask API for managing tasks to include pagination. The API should return a subset of tasks based on `limit` and `offset` query parameters.

Input Format: For fetching tasks, the API URL could look like `/tasks?offset=2&limit=3`.

Constraints:

• The `offset` will be a non-negative integer.
• The `limit` will be a positive integer.

Output Format:  

The output should be in JSON format, returning tasks based on the given `offset` and `limit`.

Sample Code:

@app.route('/tasks', methods=['GET'])

def get_tasks():

    offset = int(request.args.get('offset', 0))

    limit = int(request.args.get('limit', len(tasks)))

    paginated_tasks = tasks[offset:offset+limit]

    return jsonify(paginated_tasks)

Explanation:  

In this modification, the `get_tasks` function now uses the `offset` and `limit` query parameters to slice the `tasks` list. This way, it only returns a subset of tasks based on those parameters. It’s a simple yet effective way to implement pagination in a REST API.

3. Implement Basic Authentication

Authentication is crucial in APIs to ensure only authorized users can perform certain actions. This question tests your knowledge of implementing basic authentication in a REST API.

Task: Modify the previous Flask API for managing tasks to require basic authentication for all operations except retrieving the list of tasks (`GET` method).

Input Format: API requests should include basic authentication headers.

Constraints: For simplicity, assume a single user with a username of “admin” and a password of “password.”

Output Format: Unauthorized requests should return a 401 status code. Otherwise, the API behaves as in previous examples.

Sample Code:

from flask import Flask, jsonify, request, abort

from functools import wraps

app = Flask(__name__)

# ... (previous code for task management)

def check_auth(username, password):

    return username == 'admin' and password == 'password'

def requires_auth(f):

    @wraps(f)

    def decorated(*args, **kwargs):

        auth = request.authorization

        if not auth or not check_auth(auth.username, auth.password):

            abort(401)

        return f(*args, **kwargs)

    return decorated

@app.route('/tasks', methods=['POST', 'PUT', 'DELETE'])

@requires_auth

def manage_tasks():

    # ... (previous code for POST, PUT, DELETE methods)

Explanation:  

In this example, the `requires_auth` decorator function checks for basic authentication in incoming requests. The `check_auth` function simply validates the username and password. If the credentials are incorrect or missing, the server returns a 401 status code. This decorator is applied to routes requiring authentication (`POST`, `PUT`, `DELETE`).

4. Implement Rate Limiting

Rate limiting is used to control the amount of incoming requests to a server. This question evaluates your understanding of how to set up rate limiting in a RESTful service.

Task: Add rate limiting to your Flask API for managing tasks. Limit each client to 10 requests per minute for any type of operation.

Input Format: Standard API requests, same as previous examples.

Constraints: Rate limiting should apply per client IP address.

Output Format: Clients exceeding the rate limit should receive a 429 status code and the message “Too many requests.”

Sample Code:

from flask import Flask, jsonify, request, abort, make_response

from time import time

from functools import wraps

app = Flask(__name__)

client_times = {}

def rate_limit(f):

    @wraps(f)

    def decorated(*args, **kwargs):

        client_ip = request.remote_addr

        current_time = int(time())
    
        requests = client_times.get(client_ip, [])       

        # Filter requests in the last minute

        requests = [req_time for req_time in requests if current_time - req_time < 60]

        if len(requests) >= 10:

            return make_response(jsonify({"error": "Too many requests"}), 429)
       
        requests.append(current_time)

        client_times[client_ip] = requests
       
        return f(*args, **kwargs)
   
    return decorated

@app.route('/tasks', methods=['GET', 'POST', 'PUT', 'DELETE'])

@rate_limit

def manage_tasks():

    # ... (previous code for GET, POST, PUT, DELETE methods)

Explanation:  

The `rate_limit` decorator function checks how many times a client has made a request within the last minute. It uses a global `client_times` dictionary to keep track of these request times, keyed by client IP. If a client exceeds 10 requests, a 429 status code (“Too many requests”) is returned.

5. Implement API Versioning

When APIs evolve, maintaining different versions ensures older clients aren’t broken by new updates. This question tests your skills in implementing versioning in a RESTful service.

Task: Extend your Flask API for task management to support both a `v1` and a `v2` version. In `v2`, the task object should include an additional field called `status`.

Input Format: The version of the API should be specified in the URL, like `/v1/tasks` and `/v2/tasks`.

Constraints: The `status` field in `v2` is a string and can have values “pending,” “completed,” or “archived.”

Output Format: For `v1`, the task object remains the same as before. For `v2`, it should include the `status` field.

Sample Code:

from flask import Flask, jsonify, request

app = Flask(__name__)

tasks_v1 = []

tasks_v2 = []

task_id = 1

@app.route('/v1/tasks', methods=['GET', 'POST'])

def manage_tasks_v1():

    global task_id

    # ... (previous code for v1)

    return jsonify(tasks_v1)

@app.route('/v2/tasks', methods=['GET', 'POST'])

def manage_tasks_v2():

    global task_id

    if request.method == 'POST':

        new_task = {"id": task_id, "task": request.json['task'], "status": "pending"}

        tasks_v2.append(new_task)

        task_id += 1

        return jsonify(new_task)

    return jsonify(tasks_v2)

Explanation:  

The code includes two routes for task management, `/v1/tasks` and `/v2/tasks`. The `v1` route behaves as in previous examples. The `v2` route includes an additional `status` field in the task object, initialized to “pending” when a new task is added.

6. Custom HTTP Status Codes and Error Handling

Proper error handling and status codes make an API user-friendly and easier to debug. This question targets your knowledge of using appropriate HTTP status codes for various scenarios.

Task: Update your Flask API to return custom error messages along with appropriate HTTP status codes for different error scenarios.

Input Format: Standard API requests, same as previous examples.

Constraints:

• Return a 404 status code with a custom message if a task is not found.
• Return a 400 status code with a custom message if the input payload is missing necessary fields.

Output Format: The API should return JSON-formatted error messages along with appropriate HTTP status codes.

Sample Code:

from flask import Flask, jsonify, request, make_response

app = Flask(__name__)

tasks = []

@app.route('/tasks/<int:task_id>', methods=['GET', 'PUT', 'DELETE'])

def manage_single_task(task_id):

    task = next((item for item in tasks if item['id'] == task_id), None)

    if task is None:

        return make_response(jsonify({"error": "Task not found"}), 404)      

    if request.method == 'PUT':

        if 'task' not in request.json:

            return make_response(jsonify({"error": "Missing fields in request"}), 400)       

        task['task'] = request.json['task']

        return jsonify(task)

    # ... (previous code for GET and DELETE methods)

Explanation:  

In this example, the `manage_single_task` function first checks if the task exists. If not, it returns a 404 status code with a custom error message. If the task exists and it’s a `PUT` request but missing the ‘task’ field, it returns a 400 status code with another custom error message.

Resources to Improve REST API Knowledge

• HackerRank REST API Skills Certification
• HackerRank Interview
• Tech Interview Prep: How To Ace Your Interview

This article was written with the help of AI. Can you tell which parts?

The post 6 REST API Interview Questions Every Developer Should Know appeared first on HackerRank Blog.

Cloud technology is far more than just an industry buzzword these days; it’s the backbone of modern IT infrastructures. And among the crowded field of cloud service providers, a handful of tech companies have emerged as key players. Microsoft’s Azure, with its enormous range of services and capabilities, has solidified its position in this global market, rivaling giants like AWS and Google Cloud and quickly becoming a favorite among both businesses and developers at the forefront of cloud-based innovation. 

As Azure continues to expand its footprint across industries, the demand for professionals proficient in its ecosystem is growing too. As a result, interviews that dive deep into Azure skills are becoming more common — and for a good reason. These interviews don’t just test a candidate’s knowledge; they probe for hands-on experience and the ability to leverage Azure’s powerful features in real-world scenarios.

Whether you’re a developer eyeing a role in this domain or a recruiter seeking to better understand the technical nuances of Azure, it can be helpful to delve into questions that capture the essence of Azure’s capabilities and potential challenges. In this guide, we unravel what Azure really is, the foundations of an Azure interview, and of course, a curated set of coding questions that every Azure aficionado should be prepared to tackle.

What is Azure?

Azure is Microsoft’s answer to cloud computing — but it’s also much more than that. It’s a vast universe of interconnected services and tools designed to meet a myriad of IT needs, from the basic to the complex.

More than just a platform, Azure offers Infrastructure-as-a-Service (IaaS), providing essential resources like virtual machines and networking. It delves into Platform-as-a-Service (PaaS), where services such as Azure App Service or Azure Functions let you deploy applications without getting bogged down by infrastructure concerns. And it has software-as-a-Service (SaaS) offerings like Office 365 and Dynamics 365.

Yet, Azure’s capabilities don’t end with these three service models. It boasts specialized services for cutting-edge technologies like IoT, AI, and machine learning. From building an intelligent bot to managing a fleet of IoT devices, Azure has tools and services tailor-made for these ventures.

What an Azure Interview Looks Like

An interview focused on Azure isn’t just a test of your cloud knowledge; it’s an exploration of your expertise in harnessing the myriad services and tools that Azure offers. Given the platform’s vast expanse, the interview could span a range of topics. It could probe your understanding of deploying and configuring resources using the Azure CLI or ARM templates. Or it might assess your familiarity with storage solutions like Blob, Table, Queue, and the more recent Cosmos DB. Networking in Azure, with its virtual networks, VPNs, and Traffic Manager, is another crucial area that interviewers often touch upon. And with the increasing emphasis on real-time data and AI, expect a deep dive into Azure’s data and AI services, like machine learning or Stream Analytics.

While the nature of questions can vary widely based on the specific role, there are some common threads. Interviewers often look for hands-on experience, problem-solving ability, and a sound understanding of best practices and architectural designs within the Azure ecosystem. For instance, if you’re aiming for a role like an Azure solutions architect, expect scenarios that challenge your skills in designing scalable, resilient, and secure solutions on Azure. On the other hand, Azure DevOps engineers might find themselves solving automation puzzles, ensuring smooth CI/CD pipelines, or optimizing infrastructure as code.

But it’s not all technical! Given that Azure is often pivotal in business solutions, you might also be tested on your ability to align Azure’s capabilities with business goals, cost management, or even disaster recovery strategies.

1. Deploy a Web App Using Azure CLI

The Azure command-line interface (CLI) is an essential tool for developers and administrators to manage Azure resources. This question tests a candidate’s proficiency with Azure CLI commands, specifically focusing on deploying web applications to Azure.

Task: Write an Azure CLI script to deploy a simple web app using Azure App Service. The script should create the necessary resources, deploy a sample HTML file, and return the public URL of the web app.

Input Format: The script should accept the following parameters:

• Resource group name
• Location (e.g., “East U.S.”)
• App service plan name
• Web app name

Constraints:

• The web app should be hosted on a free tier App Service plan.
• The HTML file to be deployed should simply display “Hello Azure!”

Output Format: The script should print the public URL of the deployed web app.

Sample Code:

#!/bin/bash

# Parameters

resourceGroupName=$1

location=$2

appServicePlanName=$3

webAppName=$4

# Create a resource group

az group create --name $resourceGroupName --location $location

# Create an App Service plan on Free tier

az appservice plan create --name $appServicePlanName --resource-group $resourceGroupName --sku F1 --is-linux

# Create a web app

az webapp create --name $webAppName --resource-group $resourceGroupName --plan $appServicePlanName --runtime "NODE|14-lts"

# Deploy sample HTML file

echo "<html><body><h1>Hello Azure!</h1></body></html>" > index.html

az webapp up --resource-group $resourceGroupName --name $webAppName --html

# Print the public URL

echo "Web app deployed at: https://$webAppName.azurewebsites.net"

Explanation:

The script begins by creating a resource group using the provided name and location. It then creates an App Service plan on the free tier. Subsequently, a web app is created using Node.js as its runtime (although we’re deploying an HTML file, the runtime is still needed). A sample HTML file is then generated on the fly with the content “Hello Azure!” and deployed to the web app using `az webapp up`. Finally, the public URL of the deployed app is printed.

2. Configure Azure Blob Storage and Upload a File

Azure Blob Storage is a vital service in the Azure ecosystem, allowing users to store vast amounts of unstructured data. This question examines a developer’s understanding of Blob Storage and their proficiency in interacting with it programmatically.

Task: Write a Python script using Azure SDK to create a container in Azure Blob Storage, and then upload a file to this container.

Input Format: The script should accept the following parameters:

• Connection string
• Container name
• File path (of the file to be uploaded)

Constraints:

• Ensure the container’s access level is set to “Blob” (meaning the blobs/files can be accessed, but not the container’s metadata or file listing).
• Handle potential exceptions gracefully, like invalid connection strings or file paths.

Output Format: The script should print the URL of the uploaded blob.

Sample Code:

from azure.storage.blob import BlobServiceClient, BlobClient, ContainerClient

def upload_to_blob(connection_string, container_name, file_path):

    try:
        # Create the BlobServiceClient

        blob_service_client = BlobServiceClient.from_connection_string(connection_string)

        # Create or get container

        container_client = blob_service_client.get_container_client(container_name)

        if not container_client.exists():

            blob_service_client.create_container(container_name, public_access='blob')

        # Upload file to blob

        blob_client = blob_service_client.get_blob_client(container=container_name, blob=file_path.split('/')[-1])

        with open(file_path, "rb") as data:

            blob_client.upload_blob(data)

        print(f"File uploaded to: {blob_client.url}")     

    except Exception as e:

        print(f"An error occurred: {e}")
# Sample Usage

# upload_to_blob('<Your Connection String>', 'sample-container', 'path/to/file.txt')

Explanation:

The script uses the Azure SDK for Python. After establishing a connection with the Blob service using the provided connection string, it checks if the specified container exists. If not, it creates one with the access level set to “Blob.” The file specified in the `file_path` is then read as binary data and uploaded to the blob storage. Once the upload is successful, the URL of the blob is printed. Any exceptions encountered during these operations are caught and printed to inform the user of potential issues.

3. Azure Functions: HTTP Trigger with Cosmos DB Integration

Azure Functions, known for its serverless compute capabilities, allows developers to run code in response to specific events. Cosmos DB, on the other hand, is a multi-model database service for large-scale applications. This question assesses a developer’s ability to create an Azure Function triggered by an HTTP request and integrate it with Cosmos DB.

Task: Write an Azure Function that’s triggered by an HTTP GET request. The function should retrieve a document from an Azure Cosmos DB based on a provided ID and return the document as a JSON response.

Input Format: The function should accept an HTTP GET request with a query parameter named `docId`, representing the ID of the desired document.

Output Format: The function should return the requested document in JSON format or an error message if the document isn’t found.

Constraints:

• Use the Azure Functions 3.x runtime.
• The Cosmos DB has a database named `MyDatabase` and a container named `MyContainer`.
• Handle exceptions gracefully, ensuring proper HTTP response codes and messages.

Sample Code:

using System.IO;

using Microsoft.AspNetCore.Mvc;

using Microsoft.Azure.WebJobs;

using Microsoft.Azure.WebJobs.Extensions.Http;

using Microsoft.AspNetCore.Http;

using Microsoft.Extensions.Logging;

using Newtonsoft.Json;

using Microsoft.Azure.Documents.Client;

using Microsoft.Azure.Documents.Linq;

using System.Linq;

public static class GetDocumentFunction

{

    [FunctionName("RetrieveDocument")]

    public static IActionResult Run(

        [HttpTrigger(AuthorizationLevel.Function, "get", Route = null)] HttpRequest req,

        [CosmosDB(

            databaseName: "MyDatabase",

            collectionName: "MyContainer",

            ConnectionStringSetting = "AzureWebJobsCosmosDBConnectionString",

            Id = "{Query.docId}")] dynamic document,

        ILogger log)

    {

        log.LogInformation("C# HTTP trigger function processed a request.");

        if (document == null)

        {

            return new NotFoundObjectResult("Document not found.");

        }

        return new OkObjectResult(document);
    }
}

Explanation:

This Azure Function uses the Azure Functions 3.x runtime and is written in C#. It’s triggered by an HTTP GET request. The function leverages the CosmosDB binding to fetch a document from Cosmos DB using the provided `docId` query parameter. If the document exists, it’s returned as a JSON response. Otherwise, a 404 Not Found response is returned with an appropriate error message.

Note: This code assumes the Cosmos DB connection string is stored in an application setting named “AzureWebJobsCosmosDBConnectionString.”

4. Azure Virtual Machine: Automate VM Setup with Azure SDK for Python**

Azure Virtual Machines (VMs) are a fundamental building block in the Azure ecosystem. It’s crucial for developers to know how to automate VM creation and setup to streamline operations and ensure standardized configurations. This question assesses a developer’s understanding of the Azure SDK for Python and their ability to automate VM provisioning.

Task: Write a Python script using the Azure SDK to create a new virtual machine. The VM should run Ubuntu Server 18.04 LTS, and once set up, it should automatically install Docker.

Input Format: The script should accept the following parameters:

• Resource group name
• VM name
• Location (e.g., “East U.S.”)
• Azure subscription ID
• Client ID (for Azure service principal)
• Client secret (for Azure service principal)
• Tenant ID (for Azure service principal)

Constraints:

• Ensure the VM is of size `Standard_DS1_v2`.
• Set up the VM to use SSH key authentication.
• Assume the SSH public key is located at `~/.ssh/id_rsa.pub`.
• Handle exceptions gracefully.

Output Format: The script should print the public IP address of the created VM.

Sample Code:

from azure.identity import ClientSecretCredential

from azure.mgmt.compute import ComputeManagementClient

from azure.mgmt.network import NetworkManagementClient

from azure.mgmt.resource import ResourceManagementClient




def create_vm_with_docker(resource_group, vm_name, location, subscription_id, client_id, client_secret, tenant_id):

    # Authenticate using service principal

    credential = ClientSecretCredential(client_id=client_id, client_secret=client_secret, tenant_id=tenant_id)

    # Initialize management clients

    resource_client = ResourceManagementClient(credential, subscription_id)

    compute_client = ComputeManagementClient(credential, subscription_id)

    network_client = NetworkManagementClient(credential, subscription_id)

    # Assuming network setup, storage, etc. are in place

    # Fetch SSH public key

    with open("~/.ssh/id_rsa.pub", "r") as f:

        ssh_key = f.read().strip()

    # Define the VM parameters, including post-deployment script to install Docker

    vm_parameters = {

        #... (various VM parameters like size, OS type, etc.)

        'osProfile': {

            'computerName': vm_name,

            'adminUsername': 'azureuser',

            'linuxConfiguration': {

                'disablePasswordAuthentication': True,

                'ssh': {

                    'publicKeys': [{

                        'path': '/home/azureuser/.ssh/authorized_keys',

                        'keyData': ssh_key

                    }]

                }

            },

            'customData': "IyEvYmluL2Jhc2gKc3VkbyBhcHQtZ2V0IHVwZGF0ZSAmJiBzdWRvIGFwdC1nZXQgaW5zdGFsbCAt

            eSBkb2NrZXIuY2U="  # This is base64 encoded script for "sudo apt-get update && sudo apt-get install -y docker.ce"

        }

    }

    # Create VM

    creation_poller = compute_client.virtual_machines.create_or_update(resource_group, vm_name, vm_parameters)

    creation_poller.result()

    # Print the public IP address (assuming IP is already allocated)

    public_ip = network_client.public_ip_addresses.get(resource_group, f"{vm_name}-ip")

    print(f"Virtual Machine available at: {public_ip.ip_address}")

# Sample Usage (with parameters replaced appropriately)

# create_vm_with_docker(...)

Explanation:

The script begins by establishing authentication using the provided service principal credentials. It initializes management clients for resource, compute, and networking operations. After setting up networking and storage (which are assumed to be in place for brevity), the VM is defined with the necessary parameters. The post-deployment script installs Docker on the VM upon its first boot. Once the VM is created, its public IP address is printed.

Note: The Docker installation script is base64 encoded for brevity. In real use cases, you might use cloud-init or other provisioning tools for more complex setups.

5. Azure SQL Database: Data Migration and Querying

Azure SQL Database is a fully managed relational cloud database service for developers. The integration between applications and data becomes crucial, especially when migrating data or optimizing application performance through SQL queries.

Task: Write a Python script that does the following:

1. Connects to an Azure SQL Database using provided connection details
2. Migrates data from a CSV file into a table in the Azure SQL Database
3. Runs a query on the table to fetch data based on specific criteria

Input Format: The script should accept command line arguments in the following order:

• Connection string for the Azure SQL Database
• Path to the CSV file
• The query to run on the table

Constraints:

• The CSV file will have headers that match the column names of the target table.
• Handle exceptions gracefully, such as failed database connections, invalid SQL statements, or CSV parsing errors.

Output Format: The script should print:

• A success message after data has been migrated
• The results of the SQL query in a readable format

Sample Code:

import pyodbc

import csv

import sys

def migrate_and_query_data(conn_string, csv_path, sql_query):

    try:

        # Connect to Azure SQL Database

        conn = pyodbc.connect(conn_string)

        cursor = conn.cursor()

        # Migrate CSV data

        with open(csv_path, 'r') as file:

            reader = csv.DictReader(file)

            for row in reader:

                columns = ', '.join(row.keys())

                placeholders = ', '.join('?' for _ in row)

                query = f"INSERT INTO target_table ({columns}) VALUES ({placeholders})"

                cursor.execute(query, list(row.values()))

        print("Data migration successful!")

        # Execute SQL query and display results

        cursor.execute(sql_query)

        for row in cursor.fetchall():

            print(row)

        conn.close()

    except pyodbc.Error as e:

        print(f"Database error: {e}")

    except Exception as e:

        print(f"An error occurred: {e}")

# Sample usage (with parameters replaced appropriately)

# migrate_and_query_data(sys.argv[1], sys.argv[2], sys.argv[3])

Explanation: 

This script utilizes the `pyodbc` library to interact with Azure SQL Database. The script starts by establishing a connection to the database and then iterates through the CSV rows to insert them into the target table. After the data migration, it runs the provided SQL query and displays the results. The script ensures that database-related errors, as well as other exceptions, are captured and presented to the user.

Note: Before running this, you’d need to install the necessary Python packages, such as `pyodbc` and ensure the right drivers for Azure SQL Database are in place.

6. Azure Logic Apps with ARM Templates: Automated Data Sync

Azure Logic Apps provide a powerful serverless framework to integrate services and automate workflows. While the Azure Portal offers a user-friendly visual designer, in professional settings, especially with DevOps and CI/CD pipelines, there’s often a need to define these workflows in a more programmatic way. Enter ARM (Azure Resource Manager) templates: a declarative syntax to describe resources and configurations, ensuring idempotent deployments across environments.

Task: Taking it up a notch from the visual designer, your challenge is to implement an Azure Logic App that automates the process of syncing data between two Azure Table Storage accounts using an ARM template. This will test both your familiarity with the Logic Apps service and your ability to translate a workflow into an ARM template.

Inputs:

• Source Azure Table Storage connection details
• Destination Azure Table Storage connection details

Constraints:

• Your ARM template should define the Logic App, its trigger, actions, and any associated resources like connectors.
• The Logic App should be triggered whenever a new row is added to the source Azure Table Storage.
• Newly added rows should be replicated to the destination Azure Table Storage without any data loss or duplication.
• Any failures in data transfer should be logged appropriately.

Sample ARM Template (simplified for brevity):

{

    "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",

    "contentVersion": "1.0.0.0",

    "resources": [

        {

            "type": "Microsoft.Logic/workflows",

            "apiVersion": "2017-07-01",

            "name": "SyncAzureTablesLogicApp",

            "location": "[resourceGroup().location]",

            "properties": {

                "definition": {

                    "$schema": "...",

                    "contentVersion": "...",

                    "triggers": {

                        "When_item_is_added": {

                            "type": "ApiConnection",

                            ...

                        }

                    },

                    "actions": {

                        "Add_item_to_destination": {

                            "type": "ApiConnection",

                            ...

                        }

                    }

                },

                "parameters": { ... }

            }

        }

    ],

    "outputs": { ... }

}

Explanation:

Using ARM templates to define Azure Logic Apps provides a programmatic and version-controllable approach to designing cloud workflows. The provided ARM template is a basic structure, defining a Logic App resource and its corresponding trigger and action for syncing data between two Azure Table Storage accounts. While the ARM template in this question is simplified, a proficient Azure developer should be able to flesh out the necessary details.

To implement the full solution, candidates would need to detail the trigger for detecting new rows in the source table, the action for adding rows to the destination table, and the error-handling logic.

Resources to Improve Azure Knowledge

• HackerRank Interview
• Tech Interview Prep: How To Ace Your Interview
• How to Prepare for a Microsoft Azure Certification Exam

This article was written with the help of AI. Can you tell which parts?

The post 6 Azure Interview Questions Every Developer Should Know appeared first on HackerRank Blog.

In a world now dominated by smartphones and wearables, Android stands as a titan, powering billions of devices and shaping the mobile tech landscape. From budget phones to luxury devices, from smartwatches to TVs, Android’s versatility and adaptability have made it the OS of choice for countless manufacturers and developers. It’s no surprise, then, that Android development skills are in high demand. 

But with great demand comes some competition. To stand out, Android developers will need to be intimately familiar with the platform’s intricacies and challenges. And what better way to demonstrate that expertise than through a technical interview? This guide is here to help developers prepare for their  mobile development interviews, and to arm hiring teams with the tools they need to identify their next hire.

What is Android?

Dive into any bustling city, and you’ll likely find a common sight: people engaged with their devices. Many of these devices — be it smartphones, tablets, watches, or even car dashboards — run on Android. But to truly appreciate its prominence, we must delve deeper.

Android is an open-source operating system, primarily designed for mobile devices. Birthed by Android Inc. and later acquired by Google in 2005, it’s built on top of the Linux kernel. While originally centered around a Java interface for app development, Android’s horizon expanded with the introduction of Kotlin, a modern alternative that’s fast becoming a favorite among developers.

Over the span of its existence, Android has undergone numerous evolutions. From its early days with dessert-themed code names like Cupcake and Pie to its recent, more functionally named updates, the OS has consistently pushed the envelope in innovation, security, and performance. 

What an Android Interview Looks Like

An Android coding interview often mirrors the complexities and nuances of the platform itself. Candidates might be presented with challenges ranging from designing efficient UI layouts that adapt to multiple screen sizes to ensuring seamless data synchronization in the background, all while maintaining optimal battery performance.

One fundamental area often tested is a developer’s grasp of the Android lifecycle. Understanding how different components (like activities or services) come to life, interact, and, perhaps more importantly, cease to exist, can be the key to crafting efficient and bug-free apps. Additionally, topics such as intents, broadcast receivers, and content providers frequently find their way into these discussions, highlighting the interconnected nature of Android apps and the system they operate within.

But it’s not all about coding. System design questions can pop up, gauging a developer’s ability to architect an app that’s scalable, maintainable, and user-friendly. Debugging skills, a critical asset for any developer, can also be under the spotlight, with interviewees sometimes having to identify, explain, and solve a piece of buggy code.

So, whether you’re a seasoned developer gearing up for your next role or a recruiter aiming to refine your interview process, remember that an Android interview is more than a test — it’s an opportunity. An opportunity to showcase expertise, to identify potential, and to ensure that as Android continues to evolve, so do the professionals driving its innovation.

1. Implement a Custom ListAdapter

One of the foundational skills for any Android developer is understanding how to display lists of data efficiently. The `ListView` and its successor, the `RecyclerView`, are commonly used components for this purpose. A custom `ListAdapter` or `RecyclerView.Adapter` lets you control the look and functionality of each item in the list.

Task: Create a simple `RecyclerView.Adapter` that displays a list of user names and their ages. Each item should show the name and age side by side.

Input Format: You will be given an ArrayList of User objects. Each User object has two fields: a `String` representing the user’s name and an `int` representing their age.

Constraints:

• The list will contain between 1 and 1000 users.
• Each user’s name will be non-empty and will have at most 100 characters.
• Age will be between 0 and 120.

Output Format: The adapter should bind the data such that each item in the `RecyclerView` displays a user’s name and age side by side.

Sample Input:

“`java

ArrayList<User> users = new ArrayList<>();

users.add(new User(“Alice”, 28));

users.add(new User(“Bob”, 22));

Sample Code:

public class UserAdapter extends RecyclerView.Adapter<UserAdapter.UserViewHolder> {

    private ArrayList<User> users;

    public UserAdapter(ArrayList<User> users) {

        this.users = users;

    }

    @NonNull

    @Override

    public UserViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {

        View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.user_item, parent, false);

        return new UserViewHolder(itemView);

    }

    @Override

    public void onBindViewHolder(@NonNull UserViewHolder holder, int position) {

        User currentUser = users.get(position);

        holder.nameTextView.setText(currentUser.getName());

        holder.ageTextView.setText(String.valueOf(currentUser.getAge()));

    }

    @Override

    public int getItemCount() {

        return users.size();

    }

    static class UserViewHolder extends RecyclerView.ViewHolder {

        TextView nameTextView;

        TextView ageTextView;

        public UserViewHolder(@NonNull View itemView) {

            super(itemView);

            nameTextView = itemView.findViewById(R.id.nameTextView);

            ageTextView = itemView.findViewById(R.id.ageTextView);

        }

    }

}

Explanation:

The `UserAdapter` extends the `RecyclerView.Adapter` class, defining a custom ViewHolder, `UserViewHolder`. This ViewHolder binds to the `nameTextView` and `ageTextView` in the user item layout.

In the `onBindViewHolder` method, the adapter fetches the current User object based on the position and sets the name and age to their respective TextViews. The `getItemCount` method simply returns the size of the users list, determining how many items the `RecyclerView` will display.

2. Manage Activity Lifecycle with Configuration Changes

The Android Activity Lifecycle is fundamental to creating apps that behave correctly across different user actions and system events. One common challenge is ensuring that during configuration changes, such as screen rotations, the app doesn’t lose user data and effectively preserves its current state.

Task: Implement the necessary methods in an Activity to handle configuration changes (like screen rotation) and preserve a counter. The Activity has a button that, when pressed, increments a counter. The current value of the counter should be displayed in a TextView and should not reset upon screen rotation.

Constraints:

• The counter can range from 0 to a maximum of 1,000.
• Only the screen rotation configuration change needs to be handled.

Output Format: The TextView should display the current counter value, updating every time the button is pressed. This value should persist across configuration changes.

Sample Code:

“`java

public class CounterActivity extends AppCompatActivity {

    private static final String COUNTER_KEY = “counter_key”;

    private int counter = 0;

    private TextView counterTextView;

    private Button incrementButton;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_counter);

        counterTextView = findViewById(R.id.counterTextView);

        incrementButton = findViewById(R.id.incrementButton);

        if (savedInstanceState != null) {

            counter = savedInstanceState.getInt(COUNTER_KEY);

        }

        displayCounter();

        incrementButton.setOnClickListener(v -> {

            counter++;

            displayCounter();

        });

    }

    @Override

    protected void onSaveInstanceState(@NonNull Bundle outState) {

        super.onSaveInstanceState(outState);

        outState.putInt(COUNTER_KEY, counter);

    }

    private void displayCounter() {

        counterTextView.setText(String.valueOf(counter));

    }

}

Explanation:

This `CounterActivity` displays a counter that can be incremented with a button. The critical part is the `onSaveInstanceState` method, which is called before an Activity might be destroyed, like before a configuration change. In this method, we save the current counter value in the `Bundle` using the key `COUNTER_KEY`.

Then, in the `onCreate` method, which is called when the Activity is created or recreated (e.g., after a screen rotation), we check if there’s a saved instance state. If there is, it means the Activity is being recreated, and we restore the counter value from the `Bundle`. By doing this, we ensure that the counter value is preserved across configuration changes.

3. Implement LiveData with ViewModel

The modern Android app architecture recommends using `ViewModel` and `LiveData` to build robust, maintainable, and testable apps. `LiveData` is an observable data holder class that respects the lifecycle of app components, ensuring that UI updates are made only when necessary and avoiding potential memory leaks.

Task: Create a `ViewModel` that holds a `LiveData` integer value representing a score. The ViewModel should have methods to increment and decrement the score. Implement an Activity that observes this `LiveData` and updates a TextView with the current score. The Activity should also have buttons to increase and decrease the score.

Input Format: Initial score starts at 0.

Constraints: The score can range between 0 and 100.

Output Format: The TextView in the Activity should display the current score, updating every time the increment or decrement buttons are pressed. This value should remain consistent across configuration changes.

Sample Code:

“`java

public class ScoreViewModel extends ViewModel {

    private MutableLiveData<Integer> score = new MutableLiveData<>(0);

    public LiveData<Integer> getScore() {

        return score;

    }

    public void incrementScore() {

        score.setValue(score.getValue() + 1);

    }

    public void decrementScore() {

        if (score.getValue() > 0) {

            score.setValue(score.getValue() – 1);

        }

    }

}

public class ScoreActivity extends AppCompatActivity {

    private ScoreViewModel viewModel;

    private TextView scoreTextView;

    private Button increaseButton, decreaseButton;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_score);

        viewModel = new ViewModelProvider(this).get(ScoreViewModel.class);

        scoreTextView = findViewById(R.id.scoreTextView);

        increaseButton = findViewById(R.id.increaseButton);

        decreaseButton = findViewById(R.id.decreaseButton);

        viewModel.getScore().observe(this, score -> scoreTextView.setText(String.valueOf(score)));

        increaseButton.setOnClickListener(v -> viewModel.incrementScore());

        decreaseButton.setOnClickListener(v -> viewModel.decrementScore());

    }

}

Explanation:

The `ScoreViewModel` class extends the `ViewModel` class and contains a `MutableLiveData` object representing the score. There are methods to get the score (which returns a non-modifiable `LiveData` object), increment the score, and decrement the score (ensuring it doesn’t go below 0).

The `ScoreActivity` sets up the UI and initializes the `ScoreViewModel`. It observes the `LiveData` score, so any changes to that score will automatically update the TextView displaying it. The buttons in the Activity invoke the increment and decrement methods on the `ViewModel`, altering the score.

The beauty of this architecture is the separation of concerns: the Activity manages UI and lifecycle events, while the ViewModel manages data and logic. The LiveData ensures that UI updates respect the lifecycle, avoiding issues like memory leaks or crashes due to updates on destroyed Activities.

4. Implement a Room Database Query

The Room persistence library provides an abstraction layer over SQLite, enabling more robust database access while harnessing the full power of SQLite. It simplifies many tasks but still requires a deep understanding of SQL when querying the database.

Task: Create a Room database that has a table named `Book` with fields `id`, `title`, and `author`. Implement a DAO (Data Access Object) method that fetches all books written by a specific author.

Input Format: The `Book` table will have a primary key `id` of type `int`, a `title` of type `String`, and an `author` of type `String`.

Constraints:

• `id` is unique.
• Both `title` and `author` fields have a maximum length of 100 characters.

Output Format: The DAO method should return a List of `Book` objects written by the specified author.

Sample Code:

“`java

@Entity(tableName = “book”)

public class Book {

    @PrimaryKey

    private int id;

    @ColumnInfo(name = “title”)

    private String title;

    @ColumnInfo(name = “author”)

    private String author;

    // Constructors, getters, setters…

}

@Dao

public interface BookDao {

    @Query(“SELECT * FROM book WHERE author = :authorName”)

    List<Book> getBooksByAuthor(String authorName);

}

@Database(entities = {Book.class}, version = 1)

public abstract class AppDatabase extends RoomDatabase {

    public abstract BookDao bookDao();

}

Explanation:

The `Book` class is annotated with `@Entity`, indicating that it’s a table in the Room database. The `id` field is marked as the primary key with `@PrimaryKey`. The other fields, `title` and `author`, are annotated with `@ColumnInfo` to specify their column names in the table.

The `BookDao` interface contains a method `getBooksByAuthor` which uses the `@Query` annotation to run an SQL query to fetch all books by a given author.

Finally, `AppDatabase` class is an abstract class that extends `RoomDatabase`, and it contains an abstract method to get an instance of the `BookDao`. This class is annotated with `@Database`, specifying the entities it comprises and the version of the database.

With this setup, any Android component can get an instance of `AppDatabase`, retrieve the `BookDao`, and use it to fetch books by a specific author from the underlying SQLite database.

5. Implement RecyclerView with DiffUtil

Using `RecyclerView` is a common task in Android development. It’s efficient, especially when displaying large lists or grids of data. To further enhance its efficiency, `DiffUtil` can be used to calculate differences between old and new lists, ensuring only actual changes get animated and rendered.

Task: Create a `RecyclerView` adapter that displays a list of strings. The adapter should use `DiffUtil` to efficiently handle updates to the list.

Input Format: The adapter will take in a list of strings.

Constraints: The list can contain up to 500 strings, with each string having a maximum length of 200 characters.

Output Format: A `RecyclerView` displaying the strings, efficiently updating its content whenever there’s a change in the input list.

Sample Code:

“`java

public class StringAdapter extends RecyclerView.Adapter<StringAdapter.ViewHolder> {

    private List<String> data;

    public StringAdapter(List<String> data) {

        this.data = data;

    }

    public void updateList(List<String> newData) {

        DiffUtil.DiffResult diffResult = DiffUtil.calculateDiff(new StringDiffCallback(data, newData));

        this.data.clear();

        this.data.addAll(newData);

        diffResult.dispatchUpdatesTo(this);

    }

    @NonNull

    @Override

    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {

        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_string, parent, false);

        return new ViewHolder(view);

    }

    @Override

    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {

        holder.textView.setText(data.get(position));

    }

    @Override

    public int getItemCount() {

        return data.size();

    }

    static class ViewHolder extends RecyclerView.ViewHolder {

        TextView textView;

        public ViewHolder(@NonNull View itemView) {

            super(itemView);

            textView = itemView.findViewById(R.id.textView);

        }

    }

    static class StringDiffCallback extends DiffUtil.Callback {

        private final List<String> oldList;

        private final List<String> newList;

        public StringDiffCallback(List<String> oldList, List<String> newList) {

            this.oldList = oldList;

            this.newList = newList;

        }

        @Override

        public int getOldListSize() {

            return oldList.size();

        }

        @Override

        public int getNewListSize() {

            return newList.size();

        }

        @Override

        public boolean areItemsTheSame(int oldItemPosition, int newItemPosition) {

            return oldList.get(oldItemPosition).equals(newList.get(newItemPosition));

        }

        @Override

        public boolean areContentsTheSame(int oldItemPosition, int newItemPosition) {

            String oldString = oldList.get(oldItemPosition);

            String newString = newList.get(newItemPosition);

            return oldString.equals(newString);

        }

    }

}

Explanation:

The `StringAdapter` class extends the `RecyclerView.Adapter` and displays a list of strings. Its `updateList` method allows efficient updates using the `DiffUtil` utility. When new data is provided, `DiffUtil` calculates the difference between the old and new lists. The results, containing information about which items were added, removed, or changed, are then applied to the RecyclerView to ensure efficient updates.

The `StringDiffCallback` class, which extends `DiffUtil.Callback`, is responsible for determining the differences between two lists. The `areItemsTheSame` method checks if items (based on their position) in the old and new lists are the same, while the `areContentsTheSame` method checks if the content of items at specific positions in the old and new lists is the same.

Together, this setup ensures the `RecyclerView` updates efficiently, animating only actual changes, and avoiding unnecessary redraws.

6. Dependency Injection with Hilt

Dependency injection (DI) is a software design pattern that manages object creation and allows objects to be decoupled. In Android, Hilt is a DI library that is built on top of Dagger and simplifies its usage, making it more Android-friendly. 

Task: Use Hilt to inject a repository class into an Android ViewModel. Assume the repository provides a method `getUsers()`, which fetches a list of user names.

Input Format: A ViewModel class requiring a repository to fetch a list of user names.

Constraints:

• Use Hilt for Dependency Injection.
• The repository fetches a list of strings (user names).

Output Format: A ViewModel with an injected repository, capable of fetching and holding a list of user names.

Sample Code:

“`java

// Define a repository

public class UserRepository {

    public List<String> getUsers() {

        // Assume this method fetches user names, either from a local database, API, or other data sources.

        return Arrays.asList(“Alice”, “Bob”, “Charlie”);

    }

}

// Define a ViewModel

@HiltViewModel

public class UserViewModel extends ViewModel {

    private final UserRepository userRepository;

    @Inject

    public UserViewModel(UserRepository userRepository) {

        this.userRepository = userRepository;

    }

    public List<String> fetchUserNames() {

        return userRepository.getUsers();

    }

}

// Setting up Hilt Modules

@Module

@InstallIn(SingletonComponent.class)

public class RepositoryModule {

    @Provides

    @Singleton

    public UserRepository provideUserRepository() {

        return new UserRepository();

    }

}

Explanation:

In the given code, we start by defining a basic `UserRepository` class that simulates fetching a list of user names. 

Next, we define a `UserViewModel` class. The `@HiltViewModel` annotation tells Hilt to create an instance of this ViewModel and provides the required dependencies. The `@Inject` annotation on the constructor indicates to Hilt how to provide instances of the `UserViewModel`, in this case by injecting a `UserRepository` instance.

Lastly, a Hilt module (`RepositoryModule`) is defined using the `@Module` annotation. This module tells Hilt how to provide instances of certain types. In our example, the `provideUserRepository` method provides instances of `UserRepository`. The `@InstallIn(SingletonComponent.class)` annotation indicates that provided instances should be treated as singletons, ensuring that only one instance of `UserRepository` exists across the whole application lifecycle.

By following this setup, developers can effortlessly ensure dependencies (like the `UserRepository`) are provided to other parts of the application (like the `UserViewModel`) without manually creating and managing them.

7. Custom View with Measure and Draw

Custom views are a fundamental part of Android, allowing developers to create unique UI elements tailored to specific needs. Creating a custom view often requires understanding of the measure and draw process to ensure the view adjusts correctly to different screen sizes and resolutions.

Task: Create a simple custom view called `CircleView` that displays a colored circle. The view should have a customizable radius and color through XML attributes.

Input Format: Custom XML attributes for the `CircleView`: `circleColor` and `circleRadius`.

Constraints:

• Implement the `onMeasure` method to ensure the view adjusts correctly.
• Override the `onDraw` method to draw the circle.

Output Format: A custom view displaying a circle with specified color and radius.

Sample Code:

In `res/values/attrs.xml`:

“`xml

<declare-styleable name=”CircleView”>

    <attr name=”circleColor” format=”color” />

    <attr name=”circleRadius” format=”dimension” />

</declare-styleable>

In `CircleView.java`:

“`java

public class CircleView extends View {

    private int circleColor;

    private float circleRadius;

    private Paint paint;

    public CircleView(Context context, AttributeSet attrs) {

        super(context, attrs);

        paint = new Paint(Paint.ANTI_ALIAS_FLAG);

        TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.CircleView);

        circleColor = ta.getColor(R.styleable.CircleView_circleColor, Color.RED);

        circleRadius = ta.getDimension(R.styleable.CircleView_circleRadius, 50f);

        ta.recycle();

        paint.setColor(circleColor);

    }

    @Override

    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {

        int desiredWidth = (int) (2 * circleRadius + getPaddingLeft() + getPaddingRight());

        int desiredHeight = (int) (2 * circleRadius + getPaddingTop() + getPaddingBottom());

        int widthMode = MeasureSpec.getMode(widthMeasureSpec);

        int widthSize = MeasureSpec.getSize(widthMeasureSpec);

        int heightMode = MeasureSpec.getMode(heightMeasureSpec);

        int heightSize = MeasureSpec.getSize(heightMeasureSpec);

        int width, height;

        if (widthMode == MeasureSpec.EXACTLY) {

            width = widthSize;

        } else if (widthMode == MeasureSpec.AT_MOST) {

            width = Math.min(desiredWidth, widthSize);

        } else {

            width = desiredWidth;

        }

        if (heightMode == MeasureSpec.EXACTLY) {

            height = heightSize;

        } else if (heightMode == MeasureSpec.AT_MOST) {

            height = Math.min(desiredHeight, heightSize);

        } else {

            height = desiredHeight;

        }

        setMeasuredDimension(width, height);

    }

    @Override

    protected void onDraw(Canvas canvas) {

        float cx = getWidth() / 2f;

        float cy = getHeight() / 2f;

        canvas.drawCircle(cx, cy, circleRadius, paint);

    }

}

Explanation:

The process of crafting a custom view in Android often involves a synergy between XML for configuration and Java/Kotlin for implementation. Let’s break down how the `CircleView` operates across these two realms:

XML Custom Attributes (`attrs.xml`):

• Purpose: When creating a customizable view in Android, it’s imperative to define how it can be configured. Custom XML attributes allow the developer or designer to set specific properties directly in the layout XML files.
• In Our Example: We defined two custom attributes in `attrs.xml`: `circleColor` and `circleRadius`. These dictate the color and size of the circle respectively when the view is used in an XML layout.

Java Implementation (`CircleView.java`):

• • Purpose: This is where the rubber meets the road. The Java (or Kotlin) code handles the logic, processing, and rendering of the custom view.

• In Our Example: 

• • The constructor fetches the values of the custom attributes from the XML layout using `obtainStyledAttributes`. This means when you use the view in an XML layout and specify a color or radius, this is where it gets picked up and used.
  • The `onMeasure` method ensures the view adjusts its size according to the circle’s radius, also accounting for any padding.
  • The `onDraw` method takes care of the actual drawing of the circle, centered in the view, with the specified color and radius.

By mastering the interplay between XML attributes and Java/Kotlin logic, developers can craft custom UI elements that aren’t just visually appealing but also flexible and adaptive to various design specifications.

Resources to Improve AWS Knowledge

• HackerRank Interview
• Tech Interview Prep: How To Ace Your Interview
• Android Developer Courses

This article was written with the help of AI. Can you tell which parts?

The post 7 Android Interview Questions Every Developer Should Know appeared first on HackerRank Blog.

Cloud computing technology has firmly enveloped the world of tech, with Amazon Web Services (AWS) being one of the fundamental layers. Launched in 2006, AWS has evolved into a comprehensive suite of on-demand cloud computing platforms, tools, and services, powering millions of businesses globally.

The ubiquity of AWS is undeniable. As of Q1 2023, AWS commands 32% of the cloud market, underlining its pervasive influence. This widespread reliance on AWS reflects a continued demand for professionals adept in AWS services who can leverage its vast potential to architect scalable, resilient, and cost-efficient application infrastructures.

Companies are actively on the hunt for engineers, system architects, and DevOps engineers who can design, build, and manage AWS-based infrastructure, solve complex technical challenges, and take advantage of cutting-edge AWS technologies. Proficiency in AWS has become a highly desirable skill, vital for tech professionals looking to assert their cloud computing capabilities, and a critical criterion for recruiters looking to acquire top-tier talent.

In this article, we explore what an AWS interview typically looks like and introduce crucial AWS interview questions that every developer should be prepared to tackle. These questions are designed not only to test developers’ practical AWS skills but also to demonstrate their understanding of how AWS services interconnect to build scalable, reliable, and secure applications. Whether you’re a seasoned developer looking to assess and polish your AWS skills or a hiring manager seeking effective ways to evaluate candidates, this guide will prepare you to navigate AWS interviews with ease.

What is AWS?

Amazon Web Services, popularly known as AWS, is the reigning champ of cloud computing platforms. It’s an ever-growing collection of over 200 cloud services that include computing power, storage options, networking, and databases, to name a few. These services are sold on demand and customers pay for what they use, providing a cost-effective way to scale and grow.

AWS revolutionizes the way businesses develop and deploy applications by offering a scalable and durable platform that businesses of all sizes can leverage. Be it a promising startup or a Fortune 500 giant, many rely on AWS for a wide variety of workloads, including web and mobile applications, game development, data processing and warehousing, storage, archive, and many more.

What an AWS Interview Looks Like

Cracking an AWS interview involves more than just knowing the ins and outs of S3 buckets or EC2 instances. While a deep understanding of these services is vital, you also need to demonstrate how to use AWS resources effectively and efficiently in real-world scenarios.

An AWS interview typically tests your understanding of core AWS services, architectural best practices, security, and cost management. You could be quizzed on anything from designing scalable applications to deploying secure and robust environments on AWS. The level of complexity and depth of these questions will depend largely on the role and seniority level you are interviewing for.

AWS skills are not restricted to roles like cloud engineers or AWS solutions architects. Today, full-stack developers, DevOps engineers, data scientists, machine learning engineers, and even roles in management and sales are expected to have a certain level of familiarity with AWS. For instance, a full-stack developer might be expected to know how to deploy applications on EC2 instances or use Lambda for serverless computing, while a data scientist might need to understand how to leverage AWS’s vast suite of analytics tools.

That being said, irrespective of the role, some common themes generally crop up in an AWS interview. These include AWS’s core services like EC2, S3, VPC, Route 53, CloudFront, IAM, RDS, and DynamoDB; the ability to choose the right AWS services based on requirements; designing and deploying scalable, highly available, and fault-tolerant systems on AWS; data security and compliance; cost optimization strategies; and understanding of disaster recovery techniques.

1. Upload a File to S3

Amazon S3 (Simple Storage Service) is one of the most widely used services in AWS. It provides object storage through a web service interface and is used for backup and restore, data archiving, websites, applications, and many other tasks. In a work environment, a developer may need to upload files to S3 for storage or for further processing. Writing a script to automate this process can save a significant amount of time and effort, especially when dealing with large numbers of files. 

Task: Write a Python function that uploads a file to a specified S3 bucket.

Input Format: The input will be two strings: the first is the file path on the local machine, and the second is the S3 bucket name.

Output Format: The output will be a string representing the URL of the uploaded file in the S3 bucket.

Sample Code:

import boto3

def upload_file_to_s3(file_path, bucket_name):

    s3 = boto3.client('s3')

    file_name = file_path.split('/')[-1]

    s3.upload_file(file_path, bucket_name, file_name)

    file_url = f"https://{bucket_name}.s3.amazonaws.com/{file_name}"

    return file_url

Explanation:

This question tests a candidate’s ability to interact with AWS S3 using Boto3, the AWS SDK for Python. The function uses Boto3 to upload the file to the specified S3 bucket and then constructs and returns the file URL.

2. Launch an EC2 Instance

Amazon EC2 (Elastic Compute Cloud) is a fundamental part of many AWS applications. It provides resizable compute capacity in the cloud and can be used to launch as many or as few virtual servers as needed. Understanding how to programmatically launch and manage EC2 instances is a valuable skill for developers working on AWS, as it allows for more flexible and responsive resource allocation compared to manual management. 

Task: Write a Python function using Boto3 to launch a new EC2 instance.

Input Format: The input will be two strings: the first is the instance type, and the second is the Amazon Machine Image (AMI) ID.

Output Format: The output will be a string representing the ID of the launched EC2 instance.

Sample Code:

import boto3

def launch_ec2_instance(instance_type, image_id):

    ec2 = boto3.resource('ec2')

    instances = ec2.create_instances(

        ImageId=image_id,

        InstanceType=instance_type,

        MinCount=1,

        MaxCount=1

    )

    return instances[0].id

Explanation:

The function uses Boto3 to launch an EC2 instance with the specified instance type and AMI ID, and then returns the instance ID. This intermediate-level question tests a candidate’s knowledge of AWS EC2 operations. 

3. Read a File from S3 with Node.js

Reading data from an S3 bucket is a common operation when working with AWS. This operation is particularly important in applications involving data processing or analytics, where data stored in S3 needs to be loaded and processed by compute resources. In this context, AWS Lambda is often used for running code in response to triggers such as changes in data within an S3 bucket. Therefore, a developer should be able to read and process data stored in S3. 

Task: Write a Node.js AWS Lambda function that reads an object from an S3 bucket and logs its content.

Input Format: The input will be an event object with details of the S3 bucket and the object key.

Output Format: The output will be the content of the file, logged to the console.

Sample Code:

const AWS = require('aws-sdk');

const s3 = new AWS.S3();

exports.handler = async (event) => {

    const params = {

        Bucket: event.Records[0].s3.bucket.name,

        Key: event.Records[0].s3.object.key

    };

    const data = await s3.getObject(params).promise();

    console.log(data.Body.toString());

};

Explanation:

This advanced-level question requires knowledge of AWS SDK for JavaScript (in Node.js) and Lambda. The above AWS Lambda function is triggered by an event from S3. The function then reads the content of the S3 object and logs it. 

4. Write to a DynamoDB Table

Amazon DynamoDB is a key-value and document database that delivers single-digit millisecond performance at any scale. It’s commonly used to support web, mobile, gaming, ad tech, IoT, and many other applications that need low-latency data access. Being able to interact with DynamoDB programmatically allows developers to build more complex, responsive applications and handle data in a more flexible way.

Task: Write a Python function using Boto3 to add a new item to a DynamoDB table.

Input Format: The input will be two strings: the first is the table name, and the second is a JSON string representing the item to be added.

Output Format: The output will be the response from the DynamoDB put operation.

Sample Code:

import boto3

import json

def add_item_to_dynamodb(table_name, item_json):

    dynamodb = boto3.resource('dynamodb')

    table = dynamodb.Table(table_name)

    item = json.loads(item_json)

    response = table.put_item(Item=item)

    return response

Explanation:

This function uses Boto3 to add a new item to a DynamoDB table. The function first loads the item JSON string into a Python dictionary, then adds it to the DynamoDB table. This question tests a candidate’s knowledge of how to interact with a DynamoDB database using Boto3.

5. Delete an S3 Object

Being able to delete an object from an S3 bucket programmatically is important for maintaining data hygiene and managing storage costs. For instance, you may need to delete objects that are no longer needed to free up space and reduce storage costs, or you might need to remove data for compliance reasons. Understanding how to perform this operation through code rather than manually can save a lot of time when managing large amounts of data.

Task: Write a Node.js function to delete an object from an S3 bucket.

Input Format: The input will be two strings: the first is the bucket name, and the second is the key of the object to be deleted.

Output Format: The output will be the response from the S3 delete operation.

Sample Code:

const AWS = require('aws-sdk');

const s3 = new AWS.S3();

async function delete_s3_object(bucket, key) {

    const params = {

        Bucket: bucket,

        Key: key

    };
    const response = await s3.deleteObject(params).promise();

    return response;
}

Explanation:

The function uses the AWS SDK for JavaScript (in Node.js) to delete an object from an S3 bucket and then returns the response. This expert-level question tests the candidate’s ability to perform S3 operations using the AWS SDK.

Resources to Improve AWS Knowledge

• HackerRank Interview
• Tech Interview Prep: How To Ace Your Interview
• AWS Certification Exam Preparation

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