Seltsamer Fehler in SWING anwendung

[Benni1000]

Hallo Leute,
Ich versuche atm verzweifelt einen wahrscheinlich sehr einfachen Codingfehler zu finden.
Ich habe eine Klasse server.java die ein TCP packet empfängt und es in eine JTextarea eintragen soll. Das empfangen klappt auch wunderbar aber beim eintragen oder zugreifen auf die Area bekomme ich einen NullPointerException fehler, obwohl ich die area korrekt übergebe (in meiner main klasse).
chatFrame.java

import java.io.IOException;
import java.net.UnknownHostException;
import java.util.logging.Level;
import java.util.logging.Logger;

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

/**
 *
 * @author benni
 */
public class chatFrame extends javax.swing.JFrame {

    /**
     * Creates new form chatFrame
     */
    private server server = new server(this.jTextArea1);
    public chatFrame() {
        initComponents();
        server.start();
    }

    /**
     * This method is called from within the constructor to initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is always
     * regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">
    private void initComponents() {

        jTextField1 = new javax.swing.JTextField();
        jButton1 = new javax.swing.JButton();
        jTextField2 = new javax.swing.JTextField();
        jScrollPane1 = new javax.swing.JScrollPane();
        jTextArea1 = new javax.swing.JTextArea();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        jTextField1.setText("127.0.0.1");

        jButton1.setText("Absenden");
        jButton1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton1ActionPerformed(evt);
            }
        });

        jTextArea1.setColumns(20);
        jTextArea1.setEditable(false);
        jTextArea1.setRows(5);
        jScrollPane1.setViewportView(jTextArea1);

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                .addGap(19, 19, 19)
                .addComponent(jTextField2)
                .addGap(18, 18, 18)
                .addComponent(jButton1)
                .addGap(36, 36, 36))
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(jScrollPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 380, Short.MAX_VALUE)
                    .addGroup(layout.createSequentialGroup()
                        .addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, 113, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addGap(0, 0, Short.MAX_VALUE)))
                .addContainerGap())
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, 20, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(18, 18, 18)
                .addComponent(jScrollPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 179, Short.MAX_VALUE)
                .addGap(18, 18, 18)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jButton1)
                    .addComponent(jTextField2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGap(31, 31, 31))
        );

        pack();
    }// </editor-fold>

    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
        client client = new client(jTextField2.getText(),jTextField1.getText());
        try {
            client.client_sendMessage();
        } catch (UnknownHostException ex) {
            Logger.getLogger(chatFrame.class.getName()).log(Level.SEVERE, null, ex);
        } catch (IOException ex) {
            Logger.getLogger(chatFrame.class.getName()).log(Level.SEVERE, null, ex);
        }
    }                                        

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        /*
         * Set the Nimbus look and feel
         */
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /*
         * If Nimbus (introduced in Java SE 6) is not available, stay with the
         * default look and feel. For details see
         * [url=http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html]How to Set the Look and Feel (The Java™ Tutorials > Creating a GUI With JFC/Swing > Modifying the Look and Feel)[/url]
         */
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(chatFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(chatFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(chatFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(chatFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>

        /*
         * Create and display the form
         */
        java.awt.EventQueue.invokeLater(new Runnable() {

            public void run() {
                new chatFrame().setVisible(true);
            }
        });
    }
    // Variables declaration - do not modify
    private javax.swing.JButton jButton1;
    private javax.swing.JScrollPane jScrollPane1;
    public javax.swing.JTextArea jTextArea1;
    private javax.swing.JTextField jTextField1;
    private javax.swing.JTextField jTextField2;
    // End of variables declaration
}

server.java

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JTextArea;

public class server extends Thread{
    private JTextArea field;
    public server(JTextArea area) {
         this.field = area;
         area.setText("test");
    }
    @Override
    public void run() {
        try {
            ServerSocket ss = new ServerSocket(4000);
            while(true) {
                Socket sc = ss.accept();
                BufferedReader read = new BufferedReader(new InputStreamReader(sc.getInputStream()));
                String line= read.readLine();
                this.field.setText(""+field.getText()+line+"\n");
            }
        } catch (IOException ex) {
            Logger.getLogger(server.class.getName()).log(Level.SEVERE, null, ex);
        }
    }
}

Wie oben zu sehen erstelle ich in Zeile 20 einen neuen Server.
Müsste doch passen oder?

Mfg Benni1000

 

[Der Müde Joe]

Du erstellst in der main einen neues ChatFrame.
Zuerst werden dann alle Instanzvariblen initialiesiert.

In deinem Fall:
private server server = new server(this.jTextArea1);

Die JTextArea is zu diesem Zeitpunkt noch null.
Du übergibst dem Server also null.

Hier
this.field.setText(""+field.getText()+line+"\n");
fliegt dann die NPE, da dass Feld null ist.

 

[Benni1000]

Danke hab die Initialisierung des servers hinter das initialitieren der Komponenten verschoben jetzt funktioniert alles.