Limit number of characters in JTextField

Question

I try to limit the number of allowable characters to 5 by using

    try {
        jFormattedTextField2.setFormatterFactory(new javax.swing.text.DefaultFormatterFactory(new javax.swing.text.MaskFormatter("*****")));
    } catch (java.text.ParseException ex) {
        ex.printStackTrace();
    }

However, when I only enter 1 character, there will always be 4 others space being padded. How can I avoid the padding, at the same time limiting number of characters?

Answer 1

Instead of a JFormattedTextField, use a plain JTextField. Change the textfield's document to accept only a specific number of characters by setting a custom document.

Answer 2

JFormattedTextField leads to evil UIs.

The class you want is javax.swing.text.DocumentFilter. This allows you modify mutations in a chain-of-command style.