Creazione di un Array di JLabel

[spera]

Mi serve creare un array bidimensionale di JLabel ma contina a darmi un errore di tipo java.lang.NullPointerException

JLabel[][] labels=new JLabel[3][3];
for(int i=0;i<=3;i++){
for(int j=0;j<=3;j++){
labels[i][j].setBounds(45*i,45*j,40,40);
dxPanel.add(labels[i][j]);

}
}

L'errore completo:

java.lang.NullPointerException
at java.awt.Container.addImpl(Container.java:1086)
at java.awt.Container.add(Container.java:410)
at provaWB.Window.<init>(Window.java:196)
at provaWB.Window$1.run(Window.java:42)
at java.awt.event.InvocationEvent.dispatch(Invocation Event.java:312)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.j ava:745)
at java.awt.EventQueue.access$300(EventQueue.java:103 )
at java.awt.EventQueue$3.run(EventQueue.java:706)
at java.awt.EventQueue$3.run(EventQueue.java:704)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPri vilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java: 715)
at java.awt.EventDispatchThread.pumpOneEventForFilter s(EventDispatchThread.java:242)
at java.awt.EventDispatchThread.pumpEventsForFilter(E ventDispatchThread.java:161)
at java.awt.EventDispatchThread.pumpEventsForHierarch y(EventDispatchThread.java:150)
at java.awt.EventDispatchThread.pumpEvents(EventDispa tchThread.java:146)
at java.awt.EventDispatchThread.pumpEvents(EventDispa tchThread.java:138)
at java.awt.EventDispatchThread.run(EventDispatchThre ad.java:91)

La riga 196 di window corrisponde al setBounds