What did I do wrong? Exception in thread "main" java.lang.NoSuchMethodError: main

Question

When ever I try to compile and run this code:

import java.awt.GridLayout;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;

public abstract class screen implements ActionListener {
    private JFrame title = new JFrame("Tic-Tac-Toe");
    private JButton play = new JButton("");
    private JButton quit = new JButton("");

    public screen() {

        /* Create Window */
        title.setSize(300,300);
        title.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        title.setLayout(new GridLayout(3,3));

        /* Add Buttons To The Window */
        title.add(play);
        title.add(quit);

        /* Action Listeners */
        play.addActionListener(this);
        quit.addActionListener(this);

        /* Make The Window Visible */
        title.setVisible(true);

        /* Letters */
        play.setText("PLAY");
        quit.setText("QUIT");
    }
}

I get this:

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

I dont know what I did wrong.

I am a novice.

PLEASE HELP!!!

I see no main method here. Did you try to run this class on the command line? Start here: http://docs.oracle.com/javase/tutorial/getStarted/cupojava/win32.html — duffymo, Feb 19 '13 at 23:46
@DaveNewton would not declaring main cause java.lang.NoSuchMethodError: main ?? — PermGenError, Feb 19 '13 at 23:50
@PremGenError - Yes, that's *exactly* what causes that exception. (Though in (Oracle's) Java 7 it's now friendlier and gives you a warm fuzzy message telling you to define it instead of the exception) — Brian Roach, Feb 19 '13 at 23:56
@BrianRoach ahh k, thanks, in java 7 i got `Error: Main method not found in class B, please define the main method as: public static void main(String[] args) ` — PermGenError, Feb 19 '13 at 23:58
@PremGenError Yes, if you try to run it. Obviously not declaring it doesn't cause an error, it's also clear that's not what precipitated the error message. — Dave Newton, Feb 20 '13 at 01:29

score 0 · Answer 1 · answered Feb 19 '13 at 23:49

0

You need to declare a public static void main(String args[]) {} method.

answered Feb 19 '13 at 23:49

JoshDM

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::facepalm:: - I think you might want to start with a good beginner's book on Java rather than waving flags and hoping planes will land. – Brian Roach Feb 20 '13 at 00:08
You type it into your class. Knowledge of and use of such a method is one of the most basic of core Java skills, and as others have, I recommend you try to follow some online Java tutorials before continuing. Start here: http://docs.oracle.com/javase/tutorial/ – JoshDM Feb 20 '13 at 04:00

What did I do wrong? Exception in thread "main" java.lang.NoSuchMethodError: main

1 Answers1