Top 20 Interview Questions & Answers for COBOL Developer Roles - 2025

Are you preparing for an interview for a COBOL developer role? Look no further! This guide provides a list of top interview questions and answers to help you showcase your skills, experience, and knowledge in the latest trends and practices in COBOL development.

General Questions

• 1. Tell me about your experience with COBOL programming language.
  A: I have been working with COBOL for the past 5 years in various projects. I have a strong understanding of the language and its syntax, and I am comfortable writing and debugging complex code in COBOL.
• 2. How do you stay updated on the latest COBOL developments and updates?
  A: I regularly attend COBOL conferences and workshops, participate in online forums and groups, and constantly read articles and publications on COBOL to stay updated with the latest trends and updates in the language.
• 3. In your opinion, what are the most important skills for a COBOL developer to possess?
  A: As a COBOL developer, I believe that having strong problem-solving abilities, attention to detail, and a good understanding of business processes are essential skills. Additionally, strong coding skills, proficiency in debugging and performance tuning, and a good understanding of database systems are also important.
• 4. Can you walk me through a project where you implemented COBOL in a real-world scenario?
  A: In one of my previous projects, I was responsible for developing a COBOL-based inventory management system for a retail company. I collaborated with the business team to understand their requirements and designed a system that efficiently managed inventory levels and generated reports for stock replenishment. The project was successfully implemented and resulted in cost savings for the company.
• 5. How do you handle errors and exceptions in COBOL programs?
  A: In COBOL, I use the DISPLAY statement to identify and handle errors and exceptions. I also use the ON EXCEPTION phrase to catch specific error conditions and handle them accordingly. Additionally, I extensively test my code to ensure it is error-free before deployment.

Technical Knowledge

• 6. What are the different data types in COBOL?
  A: COBOL supports various data types such as alphanumeric, numeric, alphabetic, and special. Alphanumeric data is used to store a combination of alphabets and numbers, numeric data is used for mathematical calculations, alphabetic data is used to store alphabetic characters only, and special data is used for special characters such as currency symbols.
• 7. How do you define a record in COBOL?
  A: A record in COBOL is defined using the RECORD CONTAINS clause, followed by the name of the record and the list of fields that make up the record. The record can also have a data description entry (DD) associated with it to provide more information about the record.
• 8. What is the difference between INDEXED and SEQUENTIAL files in COBOL?
  A: In COBOL, an INDEXED file allows for random access to records using a key, while a SEQUENTIAL file can only be accessed sequentially, one record after the other.
• 9. How do you handle data errors in COBOL programs?
  A: In COBOL, I use various validation techniques such as range checks, format checks, and presence checks to handle data errors. I also use the ON SIZE ERROR phrase to handle numeric data errors, and the ON EXCEPTION phrase to handle other types of data errors.
• 10. What is the difference between a COPY and a INCLUDE statement in COBOL?
  A: The COPY statement is used to copy an entire source code from another file into the current program, while the INCLUDE statement is used to insert individual lines of code into the current program from another file. The COPY statement is usually used for larger sections of code, while the INCLUDE statement is used for smaller sections of code.

Behavioral Questions

• 11. Can you tell me about a time when you had to work under a tight deadline?
  A: In my previous job, we had a critical project that had to be completed within a tight timeframe. To meet the deadline, I worked closely with my team to prioritize tasks, delegate responsibilities, and motivate everyone to stay focused and productive. We successfully completed the project on time.
• 12. How do you handle conflicts or disagreements in a team?
  A: In my experience, open communication is key when resolving conflicts or disagreements in a team. I actively listen to all perspectives, strive to find a common ground, and work together to find a solution that benefits everyone. I also believe in maintaining a positive and respectful attitude towards my team members.
• 13. Tell me about a challenge you encountered in your previous role as a COBOL developer and how you overcame it.
  A: In my previous project, I had to develop a COBOL program to integrate with a legacy system that had outdated coding practices. After numerous debugging and troubleshooting, I was able to successfully integrate the system and update the code to meet current standards, which resulted in improved system performance.
• 14. How do you handle criticism or feedback on your work?
  A: In my experience, constructive criticism and feedback are important for professional growth. I take feedback positively and use it as an opportunity to improve my skills and work. I also actively seek feedback from my team members and superiors to constantly improve my performance.
• 15. Can you tell me about a time when you had to explain a complex technical concept to a non-technical person?
  A: In my previous job, I had to train a new team member who had no prior experience with COBOL. I used simple language and real-world examples to explain complex concepts, and I also provided hands-on training to help them understand the practical application of those concepts. The team member successfully grasped the concepts and was able to contribute to the project.

Situational Questions

• 16. How would you handle a situation where a critical production system fails due to an error in your COBOL program?
  A: I would first try to identify the root cause of the issue and find a quick fix or workaround to restore the system. Once the immediate issue is resolved, I would carefully analyze the code and implement a permanent solution to prevent similar errors in the future. I would also collaborate with other team members to ensure that the system is fully tested before deploying the fix.
• 17. How do you ensure the security of sensitive data while working on a COBOL program?
  A: In COBOL, I use various security measures such as encryption and access control to protect sensitive data. I also follow industry best practices and adhere to company policies regarding data security. Additionally, I regularly conduct security audits and keep track of any security vulnerabilities in the system.
• 18. If a client requests additional features or changes to an existing COBOL program, how would you handle it?
  A: First, I would consult with the project manager and the client to understand the scope of the requested changes and determine the impact on the existing code. Based on that, I would estimate the time and resources required for the changes and communicate it to the client. I would also suggest alternative solutions if the requested changes are not feasible within the current project timeline.
• 19. What would you do if your team is struggling to meet a project deadline?
  A: I would first try to identify the reasons for the delay and work with my team to prioritize tasks and find ways to improve efficiency. If necessary, I would also delegate tasks or request additional resources to meet the deadline. I would also communicate with project stakeholders to update them on the progress and any potential delays.
• 20. How do you handle unexpected system errors or crashes while running a COBOL program?
  A: In case of unexpected system errors or crashes, I immediately stop the program and isolate the problem area using debugging and error handling techniques. I also document the error and inform the necessary team members to troubleshoot and resolve the issue. If necessary, I also collaborate with other teams or seek assistance from external experts to find a solution.