code: public void catchException(final Label start, final Label end,
              final Type exception) {
          if (exception == null) {
              mv.visitTryCatchBlock(start, end, mark(), null);
          } else {
              mv.visitTryCatchBlock(start, end, mark(),
                      exception.getInternalName());
          }
      }
docs: Marks the start of an exception handler.
  
  @param start
  beginning of the exception handler's scope (inclusive).
  @param end
  end of the exception handler's scope (exclusive).
  @param exception
  internal name of the type of exceptions handled by the
  handler.