Best Practices on Exception Handling

We list best practices on exception handling and link to resources on the internet.

Throwing Exceptions

What are best practices for throwing exceptions?

  1. Use Exceptions only for exceptional Conditions
  2. Know Common Exceptions
  3. Failure Atomicity
  4. Never fail in Finally Block
  5. Never fail during the Construction of an Exception Instance
  6. Preserve Stack Trace
  7. Do not delegate Throwing the Exception

Handling Exceptions

What are best practices for handling exceptions?

  1. Do not ignore Exceptions
  2. Release Resources
  3. Do not log and throw
  4. Do not catch java.lang.Exception
  5. Do not analyze caught Exception
  6. Multi-Catch and Rethrow
  7. Catch late
  8. Extract try-catch Blocks

Exceptions in API Design

What are best practices for designing APIs regarding exceptions?

  1. Prefer Exceptions over Return Codes
  2. Document Exceptions with Javadoc
  3. Use own Exceptions in public API
  4. Keep Number of thrown Exceptions small
  5. Declare thrown Subclass Exceptions
  6. Declare thrown RuntimeExceptions
  7. Mind the Level of Abstraction

Designing Exceptions

What should be considered when writing new exception classes?

  1. Use existing Exceptions
  2. Choose a meaningful Name
  3. Subclass Exceptions
  4. Design Exception Class Hierarchy
  5. Know the Exception Categories
  6. Know when to use checked or unchecked Exceptions
  7. Consider to use Faults and Contingencies
  8. Provide useful Information
  9. Provide specific Information
  10. Do not change Information after the Exception is thrown
  11. Mind Serialization
  12. Provide a meaningful Message

Using smartics-exceptions

What are best practices for using the smartics-exceptions library?

  1. Dependency Magnet
  2. Error Code Index
  3. Message Bundles for Exception Codes
  4. Never analyze the Code Parameter in the Catch Block
  5. One Code Enumeration per Component