java.lang · java.base · since Java 1.0

RuntimeException

declaration
public class RuntimeException extends Exception

The unchecked-exception root: signals programming errors (violated preconditions, illegal states) that callers are not expected to recover from.

  • Standard vocabulary: IllegalArgumentException, IllegalStateException, NullPointerException, IndexOutOfBoundsException, UnsupportedOperationException (EJ 72)
  • Modern API design leans unchecked; reserve checked for genuinely recoverable conditions (EJ 70–71)