Tip of the Day: Error Handling Code Review

Error Handling

Here are some general best practices to consider around error handling code review.

These tips are by no means definitive, but serve as reminders to developers what they should consider in a checklist.

Note: error handling and general code reviews are really not separate processes.

• Invalid parameter values are handled properly early in methods (Fast Fail).
• NullPointerException conditions from method invocations are checked.
• Consider using a general error handler to handle known error conditions.
• An Error handler must clean up state and resources no matter where an error occurs.
• Avoid using RuntimeException, or sub-classes to avoid making code changes to implement correct error handling.
• Define and create custom Exception sub-classes to match your specific exception conditions. Document the exception in detail with example conditions so the developer understands the conditions for the exception.
• (JDK 7+) Use try-with-resources. (JDK < 7) check to make sure resources are closed.
• Don't pass the buck! Don't create classes which throw Exception rather than dealing with exception condition.
• Don't swallow exceptions! For example catch(Exception ignored) {}. It should at least log the exception.