Java Exception framework

Question

Please help me out to design better exception handling framework.

Answer 1

I normally implement something like the following:
interface IException {
   public boolean hasCause();
   public Throwable getCause();
   public void printStackTrace();
abstract public class AbstractException extends Exception
implements IException {
   final private Throwable cause;
   protected AbstractException(final String message) {
      this(message, null);
   protected AbstractException(final String message, final Throwable cause) {
       super(message);
       this.cause = cause;
    final public boolean hasCause() {
         return (cause != null);
    final public Throwable getCause() {
         return cause;
    final public void printStackTrace() {
          super.printStackTrace();
          if (hasCause())
               cause.printStackTrace();
}In additon to AbstractException, I also create AbstractError (extending Error) and AbstractWarning (extending Exception). When I receive an AbstractError, this indicates a non-recoverable situation. Failure to connect to database, inability to read XML config file, etc. When I receive an AbstractWarning, the servlet or front controller prompts the user to recover from a given situation. Invalid user input, missing field, etc. AbstractException encapsulates business rule violations.
By creating three separate 'flavors' of exceptions, you can substantially reduce the number of exception processing areas in your application. Normally, I allow AbstractError and AbstractWarning to propogate all the way to the servlet controller and then display a message to the user in a common way. AbstractException, for business exceptions, are sometimes handled in the domain model and other times I allow them to propogate up to the servlet controller.
- Saish