Error when trying to use a method from the client class

Question

I am doing a client/server program in Java and i have 4 classes at the moment. A GUI classe where is all the interface stuff, the client and server classes, and the News class (which is not really relevant for this).

In the GUI class i have a button, and when i press that button i want to be able to send a word from the client to the server, and get a list from the server to the client and display that list in the interface(The GUI class), i have this method in the client class that sends a word and receives an ArrayList, which is working fine:

public ArrayList<News> sendWord(String word) throws IOException {  
    String str = word;
    out.println(str);
    System.out.println(str);

    try {
        FileInputStream fileIn = new FileInputStream("/tmp/News.ser"); 
        ObjectInputStream in = new ObjectInputStream(fileIn);
        n = (ArrayList<News>) in.readObject();
        in.close();
        fileIn.close();
    } catch (IOException i) {
        i.printStackTrace();

    } catch (ClassNotFoundException c) {
        System.out.println("News class not found");
        c.printStackTrace();

    }
    return n;
}

And the GUI class i have a button listener:

JButton search = new JButton("Search");
    search.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) { 
            try {
             listNews = c.sendWord(titleText.getText());// line 106
            } catch (IOException e1) {
                e1.printStackTrace();
            }
            for (News new : listNews) { 
                    // do wtv...
            }
        }
    });

And i am instantiating the Client class like this:

private Client c;

so that i can use that method, and get the list that come from the server but i am having some issues with that, i keep getting this error:

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at GUI$2.actionPerformed(GUI.java:106)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2348)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
at java.awt.Component.processMouseEvent(Component.java:6533)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
at java.awt.Component.processEvent(Component.java:6298)
at java.awt.Container.processEvent(Container.java:2236)
at java.awt.Component.dispatchEventImpl(Component.java:4889)
at java.awt.Container.dispatchEventImpl(Container.java:2294)
at java.awt.Component.dispatchEvent(Component.java:4711)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4888)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4525)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4466)
at java.awt.Container.dispatchEventImpl(Container.java:2280)
at java.awt.Window.dispatchEventImpl(Window.java:2746)
at java.awt.Component.dispatchEvent(Component.java:4711)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:90)
at java.awt.EventQueue$4.run(EventQueue.java:731)
at java.awt.EventQueue$4.run(EventQueue.java:729)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

If you could help me i would appreciate, Thank You Guys.

"And i am instantiating the Client class like this: `private Client c;`" -- that is just **declaring** a variable, not **instantiating** it. This is a key distinction that you'd best read up on. — Hovercraft Full Of Eels, Nov 27 '17 at 00:18
Yeah i tried to do something like `private Client c = new Client();`but i got some weird error too. — mastercoder, Nov 27 '17 at 00:20
Without a valid [mcve] it's anyone's guess what's wrong with the structure of your program, but regardless, I can definitely say that your NPE is being thrown because `c` is in fact null. But it's always best for you to test to be sure -- use a debugger to see. The solution will depend on factors that we are not privy to. — Hovercraft Full Of Eels, Nov 27 '17 at 00:22
What "weird" error did you get? The error message usually will tell you *exactly* what's wrong. — Hovercraft Full Of Eels, Nov 27 '17 at 00:23
I got this error: `Exception in thread "main" java.lang.StackOverflowErrorat sun.awt.CGraphicsConfig.nativeGetBounds(Native Method) at sun.awt.CGraphicsConfig.getBounds(CGraphicsConfig.java:56) at java.awt.Window.init(Window.java:505) at java.awt.Window.(Window.java:537) at java.awt.Frame.(Frame.java:420) at javax.swing.JFrame.(JFrame.java:233)` — mastercoder, Nov 27 '17 at 00:24
Then you've got recursion going on. Perhaps you're creating a new Client *within* the Client class? Perhaps you're using some class that inappropriately extends from Client,.... hard to tell. — Hovercraft Full Of Eels, Nov 27 '17 at 00:26

Error when trying to use a method from the client class

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