Showing error messages

Exceptions are a powerful feature of Java.
Applications may recover from expected error situations and present meaningful messages to the user.

But when you catch an unexpected exception? What should you present to the user?

I propose to show a generic error message prefix requesting user feedback like:

"There was an unexpected situation, please send an email to a@b.c with the following details: "

The details are the Exception class name and, if available, the message.
Below is a method to handle exceptions this way, it should be placed in a class that extends MIDlet:

public void showExceptionAlert (Exception e) {
  StringBuffer msg = new StringBuffer(getErrorMessage());
  Display d = Display.getDisplay(this);

  msg.append(e.getClass().getName());
  if (e.getMessage() != null) {
    msg.append("\n").append(e.getMessage());
  }

  d.setCurrent(
    new Alert(getErrorTitle(), msg.toString(), 
      null /*alertImage*/, AlertType.ERROR), 
    d.getCurrent());
}

getErrorMessage() and will load the prefix getErrorTitle() the Alert title based on current locale (i18n).

Related topics:

• Internationalization (or just I18N - count the letters between I and N)