Validate Strings in Java with isEmpty, trim, and == null

A common way to validate string contents in Java using an if test, or operator, isEmpty(), trim() and == null Show a JOptionPane.showInputDialog message with predefined dropdown options. Use JOptionPane.showMessageDialog to show a confirmation. Use title, messageType, message. Extract a constant. Use a String array. Source code available on GitHub at: https://github.com/discospiff/US16Vehicles Playlist: https://www.youtube.com/playlist?list=PL73qvSDlAVVj4Q_2h9Cb4Fpr6hY5GAveS