Java gives you the ability to dynamically create strings. Even after you set the string value, you can add more characters to the string value throughout the code.

Using Java and the swing framework, provide example code for handling a text field with a single character input. Provide filters for the character inputs to restrict values to 1-9 and " ".

For new Java programmers, the JOptionPane class is a great visual and user-friendly introduction to user input and Swing-based programming. Here's how to get started.