How can I display a newline in JLabel ?

For example, if I wanted:

Hello World!

blahblahblah

This is what I have right now:

JLabel l = new JLabel("Hello World!

blahblahblah", SwingConstants.CENTER);

This is what is displayed:

Hello World!blahblahblah

Forgive me if this is a dumb question, I'm just learning some Swing basics...