Autocomplete JTextField

http://stackabuse.com/article/example-code/example-adding-autocomplete-to-jtextfield

Autocomplete can be very useful in just about any application, but its not trivial to implement. So here is a quick example of how you might do it in Java's Swing framework with JTextField (it should also work with JTextArea with only a few modifications). This example is a modified version of Oracle's example.