Cambiar icono de taza java en NetBeans

[yasmine27]

Hola, estoy intentando cambiar el icono de la taza de java y no me deja, he hecho lo siguiente:

Código Java:

public inicio2forma() {
        
        initComponents();
        setIconImage (new ImageIcon(getClass().getResource("/src/Imagentes/icono.png")).getImage());
 
        setExtendedState(JFrame.MAXIMIZED_BOTH);
 
 
 
    }
 

Y me sale el siguiente error


Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at javax.swing.ImageIcon.<init>(ImageIcon.java:205)
at Interfaz.inicio2forma.<init>(inicio2forma.java:28)
at Interfaz.inicio2forma$40.run(inicio2forma.java:772 )
at java.awt.event.InvocationEvent.dispatch(Invocation Event.java:251)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.j ava:705)
at java.awt.EventQueue.access$000(EventQueue.java:101 )
at java.awt.EventQueue$3.run(EventQueue.java:666)
at java.awt.EventQueue$3.run(EventQueue.java:664)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPri vilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java: 675)
at java.awt.EventDispatchThread.pumpOneEventForFilter s(EventDispatchThread.java:211)
at java.awt.EventDispatchThread.pumpEventsForFilter(E ventDispatchThread.java:128)
at java.awt.EventDispatchThread.pumpEventsForHierarch y(EventDispatchThread.java:117)
at java.awt.EventDispatchThread.pumpEvents(EventDispa tchThread.java:113)
at java.awt.EventDispatchThread.pumpEvents(EventDispa tchThread.java:105)
at java.awt.EventDispatchThread.run(EventDispatchThre ad.java:90)


Alguien sabe que pasa por favor???
Muchas gracias