How to limit the number of digits in a JPasswordField in Java?

Question

I have my Java code working in Eclipse but I need to add a few functionnality.

First, how to limit the number of digits that can be entered by the user ? Actually I

Answer 1

First, how to limit the number of digits that can be entered by the user ?

• See this Q&A: How To limit the number of characters in JTextField? As JPasswordField extends from JTextField it should perfectly work.
• As @nachokk correctly pointed out, working with document filters (like he does in his answer) is a more flexible option. You can read more about it in Concepts: About Documents and Implementing a Document Filter sections of Text Component Features official article.

Then, how can I play with the size of the JPassword box ? Is there a way to modify it just like a JTextField for example ? Because my line "p1.setPreferredSize(new Dimension(100, 25));" does not seem to really let me modify the size of the box.

• Don't set fixed sizes when you're working with Swing. See this topic: Should I avoid the use of set(Preferred|Maximum|Minimum)Size methods in Java Swing?.
• You can use setColumns(int columns) instead to indicate the preferred size of the text field.
• See How to Use Password Fields tutorial.