Top 20 Interview Questions & Answers for AS400 RPG Programmers – 2026

Preparing for an AS400 RPG Programmer job interview? This guide provides a list of essential questions and answers that will help you showcase your technical expertise, problem-solving abilities, and experience working with AS400 and RPG programming language. These questions cover all key areas of the job, including experience with RPG coding, debugging, and troubleshooting, as well as knowledge of AS400 systems and applications.

General Questions

• 1. Tell us about your experience with RPG programming language.
  As an AS400 RPG Programmer, I have over five years of experience working with RPG coding. I have a deep knowledge of RPG data structures and calculations, as well as experience with RPG IV, ILE RPG, andfree-format RPG.
• 2. How do you ensure your RPG code is efficient and optimized?
  I constantly strive to write clean and efficient code by following best practices and using optimization tools like RPG Toolbox. I also perform regular code reviews and revise my code as needed.
• 3. What is your experience with debugging and troubleshooting RPG programs?
  I have a strong understanding of debugging and troubleshooting techniques, and I have successfully resolved a variety of issues with RPG code, such as syntax errors, program crashes, and program logic errors.
• 4. How do you ensure your RPG programs are compatible with different versions of the AS400 system?
  I thoroughly test my RPG code on different versions of the AS400 system to ensure compatibility. I also stay updated on any changes or updates to the system that may affect my code.
• 5. How do you handle conflicting priorities or unexpected changes to project requirements?
  I am adaptable and able to quickly prioritize tasks and make necessary adjustments to meet changing project requirements. I communicate effectively with team members and stakeholders to ensure everyone is on the same page.

Technical Skills & Experience

• 6. What tools or utilities do you use for RPG development?
  I am familiar with various AS400 development tools, such as RPG Toolbox, SEU, PDM, and SDA. I also use third-party tools like Arcad and SoftLanding to improve my RPG development process.
• 7. How do you ensure data integrity in RPG programs?
  I use data validation techniques, such as data fields and data structures, to ensure data integrity in my RPG programs. I also follow best practices for database design and regularly perform data checks and maintenance.
• 8. Have you ever implemented security measures in RPG programs? If so, what were they?
  Yes, I have implemented security measures in RPG programs by adding authorization checks, implementing role-based security, and encrypting sensitive data.
• 9. Do you have any experience with AS400 system administration?
  While my role has primarily been focused on RPG programming, I do have some experience with AS400 system administration tasks such as user access management and system maintenance.
• 10. What is your experience with integrating RPG programs with other applications or systems?
  I have successfully integrated RPG programs with various systems, such as Java applications, web services, and EDI systems, using techniques like API calls and data mapping.

Problem-Solving & Decision-Making

• 11. Can you walk us through a time when you encountered a complex error in an RPG program and how you resolved it?
  While working on a project, I encountered an error that was causing the program to freeze. After carefully analyzing the code, I discovered that a variable was not being assigned a value correctly. I fixed the issue by reassigning the variable and ran thorough tests to ensure the program was functioning properly.
• 12. How do you approach a coding problem that you are unfamiliar with?
  My first step is to research and gather information about the problem. I also consult with team members and use available resources, such as documentation and online forums, to understand the issue and find a solution.
• 13. Have you ever found a more efficient way to solve a coding problem?
  Yes, I often review my code and look for ways to improve efficiency. In one instance, I found a way to optimize a loop in my code, which significantly reduced the runtime.
• 14. How do you handle a conflict with a team member or stakeholder?
  I believe in open communication and actively listen to the concerns of others. I work towards finding a mutually beneficial solution and strive to maintain a positive working relationship.
• 15. How do you handle a situation where a deadline cannot be met?
  I always strive to meet deadlines, but if a situation arises where it is not possible, I communicate this to my team and stakeholders as soon as possible and work together to find a solution, whether it be adjusting priorities or delegating tasks.

Cultural Fit

• 16. How do you ensure your work aligns with the company’s values and goals?
  I make sure to keep the company’s values and goals in mind when working on projects and decisions. I also actively seek feedback from my team and take it into consideration when making decisions.
• 17. Do you prefer working independently or as part of a team?
  I am comfortable working independently and in a team environment. I find value in both and adapt my approach based on the project and team dynamics.
• 18. How do you handle a situation where you disagree with your supervisor’s instructions?
  I would politely discuss my perspective and concerns with my supervisor to find a resolution. If ultimately, their instruction is necessary, I would follow it while still providing suggestions for improvement in the future.
• 19. How do you handle criticism or negative feedback?
  I view all feedback, whether positive or negative, as an opportunity for improvement. I take it into consideration and use it to grow and enhance my skills.
• 20. Have you ever identified a process or system improvement in your previous role? How did you get it implemented?
  Yes, while working on a project, I noticed an opportunity to improve our testing process. I discussed my idea with my supervisor and presented a plan to improve the process, which was approved and successfully implemented.