CODEWITHSUNDEEP
javaprogram-entry-pointnosuchmethoderror
user2592584
user2592584

Reputation: 29

How can i resolve the Exception in thread "main" java.lang.NoSuchMethodError: main

I have this code. Eclipse tells me that the syntax is correct but when I run the program it gives me this error:

Exception in thread "main" java.lang.NoSuchMethodError: main

What's wrong? 

import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class Main extends JFrame {

    private static final long serialVersionUID = 1L;
    public void main(String[] args){
        JFrame Main = new JFrame("TEST");
        Main.setSize(600, 600);
        Main.setLocationRelativeTo(null);
        Main.setVisible(true);
        Main.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

//Adding JPanel     
        JPanel panel = new JPanel();
        Main.add(panel);
//JPanel settings
        panel.setLayout(null);
        panel.setBackground(Color.GREEN);
//Adding JButton
        JButton button = new JButton("Button 1");
        JButton button2 = new JButton("Button2");
        panel.add(button);
        panel.add(button2);   
//Button action
        button.addActionListener(new ActionListener(){
    public void actionPerformed(ActionEvent e) {
        JPanel panel = new JPanel();
        JPanel panel2 = new JPanel();
        Main.this.getContentPane().remove(panel);
        Main.this.getContentPane().add(panel2);
        Main.this.getContentPane().validate();      
    }
});

//JButton settings
        button.setBounds(70, 160, 200, 200);
        button2.setBounds(320, 160, 200, 200);  
    }
}

Upvotes: 0

Views: 15550

Answers (7)

Manish Doshi
Manish Doshi

Reputation: 1193

The class requires a method with a signature of like this:

public static void main(String[])

Upvotes: 0

sanbhat
sanbhat

Reputation: 17622

Your main method is not static, and you should make it static. Check this to see why

public static void main(String [] args)

Upvotes: 4

gyorgyabraham
gyorgyabraham

Reputation: 2608

Your main method must be static (ie. class-bound not instance-bound) because at the time of starting your app there no class instances that could call your class' main method.

Upvotes: 0

Suresh Atta
Suresh Atta

Reputation: 122006

Your main method should be static 

  public  static  void main(String[] args){
  ----

}

And see why ??Why is the Java main method static?

Upvotes: 2

newuser
newuser

Reputation: 8466

public static void main(String[] args)

instead of 

public void main(String[] args)

public means that the method is visible and can be called from other objects of other types. Other alternatives are private, protected, package and package-private. See here for more details.

static means that the method is associated with the class, not a specific instance (object) of that class. This means that you can call a static method without creating an object of the class.

void means that the method has no return value. If the method returned an int you would write int instead of void.

The combination of all three of these is most commonly seen on the main method which most tutorials will include.

Upvotes: 1

Svend Hansen
Svend Hansen

Reputation: 3333

You have to make your main method static:

public static void main(String[] args) {

}

Upvotes: 1

Andrew Thompson
Andrew Thompson

Reputation: 168835

The class requires a method with a signature of:

public static void main(String[])

Upvotes: 1

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