Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException

Hello
I am new to Java . I am trying to develop a GUI using swings , but I am getting the error "Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException" while running the program I am trying to use Jtree to open folders stored in hard disk in tree format .
its pointing the exception error in the following line of code
cp.setLayout(new BoxLayout(cp, BoxLayout.X_AXIS));
(java.lang.NullPointerException).

Please help me regarding the same Thanks in advance

Can you post some more code please?

We can't figure out from whatever you have provided here. From the code line and exception, seems like the cp variable was not declared/initialized properly.

Goldest

Here is the declaration

JFrame frame;
cp = frame.getContentPane();

Quote:

---

Originally Posted by richirich

JFrame frame;
cp = frame.getContentPane();

---

Where are you initializing the frame? This is simple declaration.

Are you initializing it anywhere like,

Code:

---

frame = new JFrame();

---

or something like that?

If not, then NullPointerException is surely due, when you are trying to invoke anything on that frame.

Goldest