Category "jtextfield"

Adding a custom Swing component in a JFrame

I've created a simple JTextField (this will have a mask after and I'll use this in multiple projects) and I'm trying to add in a simple JFrame, however, when I

Replace 0s of jTextField as I type

I want jTextField with 12 0s and I need to change those 0s to numbers I type as I type. In begining there is 000000000000 If I type 123 then it should be 0000

How to make JTextField lose its focus?

Exacly as stated in the subject how to make JTextField lose its focus? Something like: jtf.setFocus(false)