Don’t use throws Exception or throws Throwable

Wednesday, 19 May 2004

Using throws Throwable and throws Exception subverts the exception checking system. If you do this, callers are forced to catch Throwable or Exception, which may catch both unchecked and checked exceptions. This forces callers to use instanceof to see whether the exception is one that they can deal with.

Essentially, this defers the exception-checking mechanism from compile-time to runtime, which of course converts compile-time errors to runtime errors.

On a related note, there’s not much point in specifying unchecked exception types in a throws clause, for example throws RuntimeException or throws NullPointerException. This serves no purpose except documentation, and it’s better to use a @throws javadoc comment for this, as you can include more information in the javadoc comment.


One comment

You can leave a comment, or trackback from your own site.

  1. i want clear explanation for thows exception

Leave a comment