Error Java Socket "Thread-0"

Question

i'm new to Java and i got a task to make a simple Socket program to find the Average of numbers. But i got an error when trying to run my program.

i've tried to solve this but still have no clue...

I have this Server called "server.java" and the Client called "rerata.java"

But When i try to input data on the Client which is rerata.java with field "rerata 10 2 3" it shows error like this :

Exception in thread "Thread-0" java.lang.ArrayIndexOutOfBoundsException: 4 at rerata.server.run(server.java:45)

So how to solve this please ?

This is my server.java :

package rerata;

import java.net.*;
import java.io.*;
/**
 *
 * @author GT-13
 */
public class server extends Thread{

private static int port;
private ServerSocket serverSocket;

public server(int port) throws IOException
{
    serverSocket = new ServerSocket(port);
}
@Override
public void run()
{
    while(true)
    {
        try
        {
            System.out.println(" Wait Client : !!!!");
            Socket serper = serverSocket.accept();

            DataOutputStream acc = new DataOutputStream(serper.getOutputStream());
            acc.writeUTF("OK ");

            DataInputStream arr = new DataInputStream(serper.getInputStream());

            String kata = arr.readUTF();
            String[] angka = kata.split(" ");
            float hasil = 0;
            for(int i = 1; i <= angka.length;i++)
            {
                float nilai = 0;
                nilai = Float.parseFloat(angka[i]);
                hasil += nilai;
                System.out.println(hasil);
            }
            System.out.println(hasil);
            float kirim = (hasil/(angka.length-1));
            System.out.println(kirim);
            DataOutputStream  send = new DataOutputStream(serper.getOutputStream());
            send.writeFloat(kirim);
        }
          catch (SocketTimeoutException s) {
            System.out.println("Socket timed out!");
            break;
        } catch (IOException e) {
            e.printStackTrace();
            break;
        }
    }
}
public static void main(String[] args)
{
    port = 9000;
    try
    {
        System.out.println("Server Start....");
        Thread t = new server(port);
        t.start();
    }
    catch(IOException e) 
    {
        e.printStackTrace();

     }
    }
}

And this is my rerata.java :

package rerata;

import java.io.*;
import java.net.Socket;

public class Rerata extends javax.swing.JFrame {

/**
 * Creates new form Rerata
 */
public Rerata() {
    initComponents();
}

/**
 * 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() {

    jLabel1 = new javax.swing.JLabel();
    nilai = new javax.swing.JTextField();
    excute = new javax.swing.JButton();
    jLabel2 = new javax.swing.JLabel();
    hasil = new javax.swing.JTextField();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

    jLabel1.setText("N i l a i :");

    excute.setText("Excute");
    excute.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            excuteActionPerformed(evt);
        }
    });

    jLabel2.setText("H a s i l :");

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
    getContentPane().setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(layout.createSequentialGroup()
                    .addGap(13, 13, 13)
                    .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                        .addComponent(excute)
                        .addGroup(layout.createSequentialGroup()
                            .addComponent(jLabel1)
                            .addGap(18, 18, 18)
                            .addComponent(nilai, javax.swing.GroupLayout.PREFERRED_SIZE, 253, javax.swing.GroupLayout.PREFERRED_SIZE))))
                .addGroup(layout.createSequentialGroup()
                    .addContainerGap()
                    .addComponent(jLabel2)
                    .addGap(18, 18, 18)
                    .addComponent(hasil, javax.swing.GroupLayout.PREFERRED_SIZE, 110, javax.swing.GroupLayout.PREFERRED_SIZE)))
            .addContainerGap(78, Short.MAX_VALUE))
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addGap(20, 20, 20)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                .addComponent(jLabel1)
                .addComponent(nilai, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
            .addGap(28, 28, 28)
            .addComponent(excute)
            .addGap(18, 18, 18)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                .addComponent(jLabel2)
                .addComponent(hasil, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
            .addContainerGap(171, Short.MAX_VALUE))
    );

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

private void excuteActionPerformed(java.awt.event.ActionEvent evt) {                                       
    // TODO add your handling code here:
    String sName = "localhost";
    int port = 9000;
    String angka;

    try {
        System.out.println("Client Start>>>>>"+"\n##########");
        System.out.println("Connecting to Server....\n##########");
        Socket client = new Socket(sName, port);

        OutputStream outToServer = client.getOutputStream();

        InputStream inFromServer1 = client.getInputStream();
        DataInputStream inOk = new DataInputStream(inFromServer1);
        System.out.println("Server : " + inOk.readUTF()+"\n##########");

        //System.out.println("Angka Pertama : ");
        angka = nilai.getText().trim();
        DataOutputStream outAngka1 = new DataOutputStream(outToServer);
        outAngka1.writeUTF(angka);

        InputStream inFromServer2 = client.getInputStream();
        DataInputStream inHasil = new DataInputStream(inFromServer2);
        String a = String.valueOf(inHasil.readFloat());
        hasil.setText(a);
        System.out.println(a);


        client.close();

    } catch (IOException e) {


    }
}                                      

/**
 * @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 http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
     */
    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(Rerata.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (InstantiationException ex) {
        java.util.logging.Logger.getLogger(Rerata.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (IllegalAccessException ex) {
        java.util.logging.Logger.getLogger(Rerata.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (javax.swing.UnsupportedLookAndFeelException ex) {
        java.util.logging.Logger.getLogger(Rerata.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 Rerata().setVisible(true);
        }
    });
}



 // Variables declaration - do not modify                     
    private javax.swing.JButton excute;
    private javax.swing.JTextField hasil;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JTextField nilai;
}

Alexis C. · Accepted Answer · 2013-11-15 09:34:41Z

2

for(int i = 1; i <= angka.length;i++)

Should be

for(int i = 1; i < angka.length;i++)

because arrays are 0 base indexed in Java. When you're doing

nilai = Float.parseFloat(angka[i]);

you're trying to access the element at index angka.length in the last iteration which doesn't exists.

enter image description here

edited Nov 15, 2013 at 9:34

answered Nov 15, 2013 at 9:04

Alexis C.

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2 Comments

Gilank Njeil-brik Over a year ago

when server try to split the input from client like "rerata 10 2 3". i want the array that will be process are from the second array which is 10. so it'll be like from 10 2 3

Gilank Njeil-brik Over a year ago

Thanks, Resolved. i was never too careful when it came to solving problem like this. Once again, thank you so much. :)

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