String (Throwable ex) { if (ex instanceof RuntimeException) { final Throwable cause = ex.getCause(); if (cause != null && cause != ex) { return getExceptionMessage(cause); } } else if (ex instanceof InvocationTargetException) { final Throwable target = ((InvocationTargetException)ex).getTargetException(); if (target != null && target != ex) { return getExceptionMessage(target); } } String message = ex.getMessage(); if (ex instanceof ClassNotFoundException) { message = message != null ? UIDesignerBundle.message("error.class.not.found.N", message) : UIDesignerBundle.message("error.class.not.found"); } else if (ex instanceof NoClassDefFoundError) { message = message != null ? UIDesignerBundle.message("error.required.class.not.found.N", message) : UIDesignerBundle.message("error.required.class.not.found"); } return message; }