Error Handling

Two types of exceptions

• Expected or business exceptions ~ checked?

• Unexpected program or environment errors ~ unchecked?

Good Practices

• Prefer exceptions to return codes - decreases pollution of clients

• Prefer exception types to exception payload - error codes

• Provide context for exception:

  • chain exceptions when wrapping

  • add erroneous object(s)

• Do not return null - throw exception (e.g. IllegalArgumentException)

• Prefer runtime exceptions to checked exceptions - decreases pollution and dependency

• Wrap exceptions in module or service specific exceptions - decrease dependency

• Only unexpected exceptions should be logged on error level with stack-trace.

Bad Practices

• Swallow exceptions

• Implement business logic in catch block

• Do not catch exceptions unless you handle them

• handleError() type of methods -

  • not readable what they do

  • they cheat the compiler too