Code review checklist for Java developers

Upasana | October 16, 2020 | | 24 views

Apart from functional requirements, here is the code review checklist while reviewing any Java code:

Clean Code

Code should be clean and follow design patterns wherever applicable

  • High Cohesion and Loose Coupling

  • Design Patterns - DRY and SRP

  • is there a potential for useful abstractions


Thread-safety and concurrency related guidelines

  • Do not create adhoc threads, instead use shared Executors wherever possible.

  • Immutability for better thread-safety.

  • Synchronize access to shared mutable data.

  • Use non-blocking libraries and framework (webflux, kotlin coroutines), where needed.


Existing libraries and methods should be reused wherever possible. Do not reinvent the wheels.

  • Time and Memory complexity of the code.

  • Release resources after use (File Handles, db connections, etc)

  • Avoid dynamic SQL, use prepared statements

Error Handling
  • Proper error handling for negative scenarios, input should be validated before any processing.

  • Use checked exceptions for recoverable conditions and runtime exceptions for programming errors

  • Classes and methods should be small in terms of number of lines.

  • Explain yourself in the code.

  • Use Guava or Apache commons libraries wherever possible.

  • Did I grasp the concepts in a reasonable amount of time by looking at the code?

Code Convention & Consistency
  • Meaningful naming convention, code should explain itself. Name of the variables, methods and classes should be intention revealing in nature.

  • Standard Code formatting across project

  • Code consistency with the existing culture of writing the code

  • Consistent method signatures (return optional instead of null for Java code)

  • Side effect on existing code, does this change break backward compatibility? Versioing of endpoint!

  • OWASP standards for the security

  • Do not log any sensitive information, neither put it into the query parameters.

Inter service communication
  • Whether synchronous inter service communication can be avoided?

  • How to handle service invocation failures

  • Can we use non-blocking mechanism for inter service communication?

  • Using Pub/Sub or event driven approach instead of synchronous communication wherever possible

Unit Testing

Proper unit tests that covers the functional requirements.

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