62 IBM RPG interview questions to ask your applicants

Hiring the right IBM RPG developer can be challenging for recruiters and hiring managers. This list of interview questions is designed to help you identify candidates with the necessary skills and experience.

In this blog post, we'll provide a comprehensive set of IBM RPG interview questions, segmented into categories such as general questions, junior developer questions, debugging techniques, code optimization, and situational questions. These questions will help you assess the various competencies required for the role.

Using this guide will streamline your interview process, ensuring you make informed hiring decisions. For a more thorough evaluation, consider our IBM RPG online test in conjunction with these interview questions.

Table of contents

8 general IBM RPG interview questions and answers

Ready to dive into the world of IBM RPG? These 8 general interview questions will help you assess candidates' knowledge and experience with this trusty programming language. Use them to spark discussions, gauge problem-solving skills, and uncover how well applicants understand RPG's role in modern business applications.

1. Can you explain what RPG stands for and its primary use in business applications?

RPG stands for Report Program Generator. It's a high-level programming language developed by IBM, primarily used for business applications and data processing tasks on IBM midrange computers.

A strong candidate should mention that RPG is particularly well-suited for generating reports, handling database operations, and creating business-oriented applications. They might also touch on its evolution from RPG II to RPG IV (ILE RPG) and its continued relevance in modern business environments.

Look for answers that demonstrate an understanding of RPG's historical context and its current role in maintaining and developing legacy systems for businesses.

2. How does RPG differ from other programming languages you've worked with?

RPG is unique in several ways compared to other programming languages. Some key differences include:

• Its column-sensitive nature in earlier versions (though free-form RPG is now available)

• Built-in database integration, particularly with DB2 for IBM i

• Strong focus on business logic and report generation

• Integrated Language Environment (ILE) capabilities

An ideal response should highlight RPG's strengths in handling business logic and data processing tasks efficiently. Candidates might compare it to languages like Java or C# in terms of syntax or functionality.

Pay attention to answers that show an appreciation for RPG's specific strengths while also acknowledging areas where other languages might have advantages. This demonstrates a balanced understanding of programming paradigms.

3. Describe a challenging RPG project you've worked on and how you overcame any obstacles.

This question allows candidates to showcase their practical experience with RPG and their problem-solving skills. A good answer might include:

• A brief description of the project's goals and complexity

• Specific technical challenges encountered (e.g., performance issues, integration with modern systems)

• Strategies used to overcome these challenges (e.g., code optimization, leveraging ILE features)

• The outcome of the project and lessons learned

Look for responses that demonstrate the candidate's ability to apply RPG effectively in real-world scenarios. Pay attention to how they approach problems and their willingness to learn and adapt their RPG skills to meet modern business needs.

4. How do you ensure code maintainability when working with RPG?

Maintaining RPG code, especially in legacy systems, can be challenging. A strong answer should touch on several best practices:

• Writing clean, well-commented code

• Using meaningful variable and procedure names

• Modularizing code into reusable procedures or service programs

• Implementing consistent coding standards across the team

• Leveraging modern RPG features like free-form syntax for better readability

• Regular code reviews and documentation updates

An ideal candidate will emphasize the importance of writing code with future maintenance in mind. They might also mention tools or techniques they use to improve code quality and reduce technical debt in RPG projects.

5. How do you approach integrating RPG applications with modern web technologies?

This question assesses a candidate's ability to bridge the gap between traditional RPG systems and modern web technologies. A comprehensive answer might include:

• Using web services (REST or SOAP) to expose RPG functionality

• Implementing JSON or XML for data exchange

• Leveraging IBM's Integrated Web Services (IWS) for RPG

• Utilizing frameworks like CGIDEV2 for web-enabling RPG programs

• Considering microservices architecture to modernize RPG applications gradually

Look for candidates who demonstrate an understanding of both RPG's capabilities and modern web development principles. Their approach should balance preserving existing RPG investments while enabling integration with contemporary technologies.

6. What strategies do you use for optimizing RPG program performance?

Performance optimization is crucial for RPG applications, especially in data-intensive business environments. A strong answer might include:

• Efficient use of indexing for database operations

• Minimizing I/O operations through techniques like batch processing

• Leveraging SQL for complex data retrieval instead of record-level access

• Using ILE modules and service programs for better code organization and reuse

• Implementing proper memory management techniques

• Utilizing RPG's built-in functions and op-codes for optimized operations

Ideal candidates should demonstrate an understanding of RPG's performance characteristics and show experience in identifying and resolving bottlenecks. Look for answers that balance theoretical knowledge with practical examples from their past projects.

7. How do you stay updated with the latest developments in RPG and IBM i technology?

Staying current with RPG and IBM i technologies is essential for any RPG developer. Strong answers might mention:

• Following IBM developerWorks and official IBM i documentation

• Participating in RPG and IBM i focused forums and online communities

• Attending conferences like COMMON or local user group meetings

• Reading industry publications and blogs dedicated to RPG and IBM i

• Experimenting with new RPG features in personal or work projects

Look for candidates who show a genuine interest in continuous learning and staying abreast of industry trends. Their answer should reflect a proactive approach to professional development and a commitment to enhancing their RPG skills.

8. Can you explain the concept of ILE (Integrated Language Environment) and its benefits for RPG programming?

ILE (Integrated Language Environment) is a significant advancement in the RPG ecosystem. A comprehensive answer should cover:

• Definition of ILE as an environment that allows different programming languages to work together seamlessly

• Benefits such as modular programming, better code organization, and improved performance

• The ability to create service programs and modules for code reusability

• Support for binding multiple modules written in different ILE languages (RPG, COBOL, C)

• Enhanced debugging capabilities across modules and languages

Look for candidates who can articulate how ILE has transformed RPG programming and its practical implications for modern application development. They should demonstrate an understanding of how ILE features can be leveraged to create more efficient and maintainable RPG applications.

20 IBM RPG interview questions to ask junior developers

To determine whether your applicants have the right skills to excel as junior IBM RPG developers, ask them some of these targeted interview questions. This list will help you gauge their technical understanding and problem-solving abilities, ensuring they fit the specific needs of your team. For additional insights on selecting the right candidates, check out this application developer job description.

1. What are the primary data types used in RPG, and how do you choose which to use?
2. Can you describe how to use arrays in RPG and provide an example of their application?
3. Explain the difference between fixed-format and free-format RPG. Which one do you prefer and why?
4. How do you handle file I/O operations in RPG?
5. What are subfiles and how do you use them in RPG development?
6. Can you explain how error handling is managed in RPG?
7. Describe the process of debugging an RPG program.
8. What are activation groups in RPG, and why are they important?
9. How do you implement modular programming in RPG?
10. Can you describe the use of data structures in RPG? Provide an example of when you would use them.
11. What are indicators in RPG, and how are they used?
12. How do you manage and use built-in functions in RPG?
13. Explain how to use prototypes and procedure interfaces in RPG.
14. What is the significance of the H-spec in RPG?
15. How do you perform string manipulation in RPG?
16. Describe the process of working with multi-format logical files in RPG.
17. Can you explain the role of *INLR in RPG and its impact on program execution?
18. What are some common built-in functions (BIFs) in RPG, and how do you use them?
19. How do you approach testing and validating RPG programs?
20. Can you describe an RPG cycle and its components?

9 IBM RPG interview questions and answers related to debugging techniques

To effectively evaluate candidates' proficiency in IBM RPG debugging techniques, you can ask them the following questions. These questions are designed to help you assess their problem-solving skills and their ability to troubleshoot code, ensuring they can handle real-world debugging scenarios in your organization.

1. Can you describe the different debugging tools available for RPG and how you use them?

Candidates should mention tools such as the IBM i Debugger, STRDBG, and RDi integrated debugger. They might explain how these tools help set breakpoints, monitor variables, and step through code to identify issues.

Look for responses that demonstrate familiarity with these tools and practical experience using them. Ideal candidates should also mention any preferences or specific scenarios where one tool is more effective than another.

2. How do you approach debugging when you encounter an unexpected error in an RPG program?

A systematic approach is key. Candidates might start by reviewing the error messages and logs, then isolating the problematic section of the code. They may also mention using breakpoints and stepping through the code to understand the flow and identify where things go wrong.

A good answer should reflect a logical and methodical approach to debugging. Candidates who can provide examples of past experiences troubleshooting errors will stand out.

3. How do you handle debugging in a production environment where changes must be minimal?

Candidates might explain that in production environments, they prefer using non-intrusive methods like logging and monitoring tools. They might also discuss the importance of replicating the issue in a test environment before applying any fixes.

Look for answers that emphasize caution and thorough testing. Ideal candidates should demonstrate an understanding of the risks involved in debugging live systems and how to mitigate them.

4. What strategies do you use for identifying and fixing performance issues in RPG programs?

Candidates should mention profiling tools and techniques for measuring performance, such as analyzing CPU usage and memory allocation. They may also discuss optimizing algorithms and queries, as well as reviewing code for inefficiencies.

Strong candidates will showcase their ability to diagnose and address performance bottlenecks effectively. They should also highlight any specific tools or methods they have found particularly useful.

5. Can you explain how you use logging to debug RPG programs?

Effective candidates might discuss the importance of strategically placing log statements to capture key events and data points within the program. They may also explain how they use different log levels (e.g., info, debug, error) to filter and analyze logs more efficiently.

Look for responses that show a clear understanding of logging best practices and how to use logs to trace and diagnose issues. Candidates who provide examples of how logging helped them resolve specific problems will be more compelling.

6. How do you debug issues that only occur under specific conditions or with particular data sets in RPG?

Candidates might explain their approach to replicating the issue by creating test cases that mimic the specific conditions or data sets causing the problem. They may also discuss techniques like conditional breakpoints or using debug tools to inspect data at runtime.

An ideal answer will reflect a systematic approach to isolating and reproducing the issue. Candidates who can provide insights into their problem-solving process and past experiences will be more convincing.

7. What are some common pitfalls in RPG programming that can lead to bugs, and how do you avoid them?

Candidates should identify common pitfalls such as uninitialized variables, incorrect data type usage, and off-by-one errors in loops. They might discuss practices like code reviews, unit testing, and adhering to coding standards to minimize these issues.

Look for answers that show awareness of typical RPG programming challenges and proactive measures to prevent them. Candidates who can articulate their preventive strategies and past experiences will stand out.

8. How do you document the debugging process for future reference or for team members?

Effective candidates might explain how they maintain detailed logs of their debugging sessions, including the steps taken, tools used, and solutions applied. They may also mention documenting any changes made to the code and updating relevant comments or documentation.

Look for responses that emphasize thorough documentation practices and the importance of knowledge sharing within the team. Candidates who can demonstrate their commitment to maintaining clear and comprehensive records will be more compelling.

9. Can you describe a time when you found a particularly tricky bug in an RPG program? How did you resolve it?

Candidates should provide a specific example, detailing the nature of the bug, the steps they took to diagnose and isolate it, and the eventual solution. They might also discuss any tools or techniques that were particularly helpful.

An ideal answer will showcase the candidate's problem-solving skills and persistence. Look for responses that highlight their ability to think critically and creatively to resolve complex issues.

13 IBM RPG questions related to code optimization

To assess a candidate's ability to write efficient and optimized RPG code, consider asking these 13 questions during your interview process. These questions will help you evaluate an application developer's understanding of RPG-specific optimization techniques and best practices.

1. How would you optimize an RPG program that processes large volumes of data?
2. What techniques do you use to reduce the number of I/O operations in an RPG program?
3. Can you explain the benefits of using SQL in RPG programs for data access?
4. How do you minimize the use of work fields in RPG to improve performance?
5. What role does proper indexing play in optimizing RPG programs that access databases?
6. How can you use compiler directives to optimize RPG code?
7. What strategies do you employ to reduce CPU usage in RPG programs?
8. How do you optimize RPG programs that involve complex calculations?
9. Can you describe how to use embedded SQL effectively in RPG for better performance?
10. What are some common RPG coding practices that can lead to poor performance?
11. How do you optimize memory usage in RPG programs?
12. Can you explain the benefits of using static binding for service programs in RPG?
13. How do you approach optimizing legacy RPG code without completely rewriting it?

12 situational IBM RPG interview questions for hiring top developers

To assess a candidate's ability to handle real-world scenarios in IBM RPG development, consider using these situational interview questions. These questions help evaluate how application developers approach common challenges and implement best practices in RPG programming.

1. You've been tasked with modernizing a legacy RPG program. How would you approach this project, and what steps would you take to ensure a smooth transition?
2. A client reports that their RPG application is running slowly during peak hours. How would you diagnose and address this performance issue?
3. You need to integrate an existing RPG application with a new web service. What considerations would you keep in mind, and how would you implement this integration?
4. Your team is transitioning from fixed-format to free-format RPG. How would you manage this transition and ensure code consistency across the project?
5. You've discovered a critical bug in a production RPG program. What steps would you take to identify, fix, and deploy the solution with minimal disruption?
6. A junior developer on your team is struggling with RPG concepts. How would you mentor them and help improve their skills?
7. You need to implement a new feature that requires complex data manipulation in RPG. How would you approach this task to ensure efficiency and maintainability?
8. Your RPG application needs to interact with a REST API. How would you implement this functionality within the RPG program?
9. You're tasked with improving the security of an existing RPG application. What areas would you focus on, and what changes would you recommend?
10. A client wants to migrate their RPG application to the cloud. What considerations and steps would you take to facilitate this migration?
11. You need to implement error logging and monitoring in a large RPG application. How would you approach this task to ensure comprehensive error tracking?
12. Your team is considering adopting agile methodologies for RPG development. How would you adapt RPG programming practices to fit an agile workflow?

Which IBM RPG skills should you evaluate during the interview phase?

While one interview may not provide a complete picture of a candidate's capabilities, certain core skills in IBM RPG stand out as essential for success in this role. Focusing on these key skills will help ensure that you assess the candidate's readiness to contribute effectively from day one.

IBM RPG Syntax Knowledge

Consider using an assessment test with relevant multiple-choice questions to evaluate this skill effectively. You can check out our IBM RPG test for a comprehensive evaluation.

To further delve into this skill during the interview, you can ask targeted questions that test the candidate's knowledge of syntax nuances.

Can you explain the difference between the READ and READE opcodes in IBM RPG?

When asking this question, look for clarity in the explanation, as well as an understanding of how each opcode operates in the context of file processing.

Debugging Techniques

You can filter candidates based on their understanding of debugging through an assessment test with targeted MCQs. Check our IBM RPG test for relevant content.

Another way to gauge this skill is by asking specific questions that probe the candidate's debugging strategies.

What steps would you take to troubleshoot a program that is producing incorrect output?

Listen for a structured approach that includes identifying the issue, isolating parts of the code, and testing solutions. Strong candidates should demonstrate a logical thought process.

Code Optimization Skills

You might consider using an MCQ assessment to evaluate candidates' knowledge of optimization techniques. Our IBM RPG test can help in this area.

During the interview, you can also ask questions that explore their experience with optimization.

Can you describe some common techniques you use to optimize RPG code?

Look for candidates who mention techniques such as avoiding unnecessary I/O operations, efficient use of data structures, or eliminating loop redundancies. Their answers should reflect a solid understanding of performance best practices.

Tips for Effective IBM RPG Interviews

Before putting your newfound knowledge to use, consider these tips to enhance your IBM RPG interview process. These suggestions will help you make the most of your candidate evaluations.

1. Incorporate Skills Tests in Your Screening Process

Skills tests provide objective data on a candidate's abilities before the interview stage. They help you focus on the most qualified candidates and prepare targeted questions.

For IBM RPG roles, consider using tests that evaluate related skills such as COBOL, Mainframe, and SQL. These assessments can gauge a candidate's proficiency in complementary technologies often used alongside RPG.

Implement these tests after initial resume screening but before interviews. This approach saves time by ensuring you only interview candidates with the necessary technical skills for the role.

2. Prepare a Balanced Set of Interview Questions

With limited interview time, it's crucial to ask the right questions. Balance technical RPG questions with those that assess problem-solving and adaptability.

Include questions about database management and system processes, as these are often integral to RPG development roles. This combination will give you a well-rounded view of the candidate's capabilities.

3. Master the Art of Follow-Up Questions

Asking follow-up questions is key to understanding a candidate's true depth of knowledge. It helps distinguish between memorized answers and genuine understanding.

For example, after asking about RPG's fixed-format coding, follow up with a question about how they've adapted to free-format RPG. This reveals their experience with evolving RPG standards and their ability to learn new techniques.

Streamline Your IBM RPG Hiring Process with Skills Tests

Looking to hire talented IBM RPG developers? Make sure you accurately assess their skills. The most effective way to do this is by using IBM RPG skills tests. These tests help you quickly identify top candidates with the right technical abilities.

After using skills tests to shortlist the best applicants, you can invite them for interviews. Ready to improve your hiring process? Sign up to access our IBM RPG skills tests and other programming assessments to find your ideal candidates.

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