###@###.### 2004-04-19

J2SE Version (please include all output from java -version flag):
  java version "1.5.0-beta2"
  Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0-beta2-b44)
  Java HotSpot(TM) Client VM (build 1.5.0-beta2-b46, mixed mode, sharing)

Does this problem occur on J2SE 1.3.x or 1.4.x? Yes / No (pick one)
  no

Operating System Configuration Information (be specific):
  WinXP

Hardware Configuration Information (be specific):
  Dell Optiplex

Bug Description:
  Throws.initCause() returns Throwable. We are guaranteed that it will
  return the object it was called on, and therefore that the type will
  match what it was called on. However, we currently have to cast from
  Throwable to the right type.

Steps to Reproduce (be specific):
  To use initCause(), we have to use this pattern:
    throw (TheirException) new TheirException().initCause(cause);

  If Throwable was re-defined as Throwable<T extends Throwable> and
  Throwable initCause(Throwable) became T initCause(Throwable) then this
  code could become:

    throw new TheirException().initCause(cause);

  To make use of this, all classes implementing Throwable would need to be
  declared as:

    MyException<MyException>

  This is fairly trivial for an IDE to do, or for a java 'type' like enum
  to do in the compiler.

  I guess on the down-side, initCause() is often used with legacy
  exceptions, which by deffinition means that the maintainer won't be
  refactoring the code any time soon.