Effective Java 60 Favor the use of standard exceptions

时间:2022-08-13 20:43:17

Benefits to reuse preexisting exceptions

  1. It makes your API easier to learn and use.
  2. Programs using your API are easier to read.
  3. Fewer exception classes mean a smaller memory footprint and less time spent loading classes.

Common Exceptions

Exception

Occasion for Use

IllegalArgumentException

Non-null parameter value is inappropriate

IllegalStateException

Object state is inappropriate for method invocation

NullPointerException

Parameter value is null where prohibited

IndexOutOfBoundsException

Index parameter value is out of range

ConcurrentModificationException

Concurrent modification of an object has been detected where it is prohibited

UnsupportedOperationException

Object does not support method

Principle

  1. Reuse must be based on semantics, not just on name.
  2. Also, feel free to subclass an existing exception if you want to add a bit more failure-capture information (Item 63).