JavaCodeGuidelines

A code review checklist for Java/Android projects.

Java

General

• Does the project pass all tests on the CI server?
• Is there any repetition in the code which can be avoided?
• Have the toString/equals/hashcode methods been implemented on model classes?

Stylistic

• Are there any excessively long lines (>120 chars)?
• Are there any excessively large methods/classes?
• Could any of the methods/classes/variables have a more appropriate name?
• Is the code formatted similarly to the rest of the project?
• Are there enough comments?

Error Handling

• Are stream resources closed?
• Are all exceptions handled?
• Does the code check for null references and handle them appropriately?
• Are method parameters validated if the code relies on assumptions (e.g. non-null, between 0-100)?

Mutability

• Is the accessibility level (public/protected/package/private) appropriate for all fields/methods/classes?
• Can it be final?
• Can the method return an empty List rather than null?

Android

• Are listeners/receivers deregistered in the appropriate lifecycle method?
• Are there any references to views/activities/fragments/inner classes/async tasks which might leak memory?
• Do any long operations (disk io/network) run on a background thread?
• Are there any potential performance issues (e.g. unnecessary parent views, not using ViewHolder pattern)?
• Are user input fields validated?
• Does it use ButterKnife/latest technologies?