Java code review checklist with example

Java Code Review Checklist

I consider the following points a MUST for any Java developer for when he/she is reviewing some Java code changes.

Checklist for developers

Code Quality

• Basic Checks (before)
  • The code compiles
  • Old unit tests pass
• The code was tested
  • The code was developer-tested
  • The new code must be covered by unit tests
  • Any refactoring must be covered by unit tests
  • At least 80% coverage for the code changes
  • [EMP] Unit tests should be compliant to the standards posted here
• Clean Code
  • Naming Conventions (classes, constants, variables, methods (void vs return), etc)
  • No hard-coded variables
  • Indentation
  • No spelling mistakes
  • The code does what it says it does
  • The code is easy to read (Readability)
  • Avoid duplicate code
  • Check if the code could be replaced by calling functions in other libraries/components
• Best Practices
  • OOP Principles are correctly used
  • The code follows the SOLID PRINCIPLES
  • Design Patterns
    • Recommend a design pattern when you fill that a pattern could fit there
• Exception Handling
  • Ensure that each exception is raised and handled correctly
  • Ensure that you have a well-defined exception hierarchy
  • Split the exceptions in two types: technical and business

Branching Strategy

Application Structure

• Ensure that your changes are correctly written on layers and it respects the Spring Boo App Structure
• Do not mixt up a Rest Service with a Web App (like Spring Rest with Spring MVC )

Model

• Understand the meaning of each model you defined and treat it like the most appropiate terminology for it: DTO (form for MVC), entity, Value Object, Java Bean
• Place it in the correct package
• For more details check this page [TODO link to be provided]

Rest API

• Ensure your Rest API respects the REST maturity levels
• Error Codes
  • Ensure that in case of any error or exception the API replies with the standard error codes (defined at the system level)
  • Do not write Rest API which have different directions for receiving requestions from
    • Example: having a service which facilitates communication with an external 3rd party, do not expose the same service for the 3rd party to request back, for this use a different service (e.g. a notification service)
    • You can get into a confusion when you have to handle differently the same exception in the service, but it comes from different directions, you have 2 clients and cannot reply with the same error codes (one should be internally and the other one specific to the 3rd party)
• DTO
  • Use DTO pattern for passing data between controller and service layer (at least when using sensitive or aggregated data)

MVC

• Ensure that your Model-View-Controller parts of the Web Application are compliant to the Best Practices
  • JSP don't have business logic (no Java code, only JSTL, Spring or Thymeleaf tags)
  • Model doesn't have business logic
  • Controller delegates the requests to the business (service) layer, it doesn't have logic
  • Use DTO (classes ending with Form in case of MVC) pattern for passing data between controller and service layer (at least when using sensitive or aggregated data)

Performance

• Release resources (HTTP connections, DB connections, Files, any I/O streams )

Security

Thead-safety

• Ensure your code is not a candidate for race conditions and deadlocks

Logging

Alerting

Code Quality

Clean Code

Ensure that the code is clean as much as possible. Check also that SOLID principles are followed TODO Link to be provided

Design Patterns

Recommend a design pattern where is the case

Naming Conventions

App Structure

Check that the changes are correctly written on layers and it respects the Spring Boot App Structure Do not mixt up a Rest Service with a Web App

Model

Understand the meaning of usage of each model and try to find where is the most appropriate to be placed as TODO - link to be provided

Exception Handling

Ensure that each exception is raised and handled correctly TODO - Link to be provided

Unit Testing

Coverage of minimum 80% Ensure that all corner cases are covered and it follows the unit testing standards TODO - Link to be provided

Rest API

Ensure that the API changes respect the REST maturity levels - TODO - Link to be provided

Error Codes

Ensure that in case of a program error or exception, the API replies with the standard error codes TODO - Link to be provided Bad example is Hubject-Adapter

MVC

Ensure that the Model-View-Controller parts of the Web Application are compliant with the Best Practices TODO - Link to be provided

Alerts