JFrame opens over and over again

Question

I'm having troubles with this program. Everything works, but the program keeps opening the JFrame over and over again (and obviously, I only want just one JFrame to be opened). What is wrong with my code?

Thank you in advance, Stefan

 import java.util.*;
    import java.awt.*;
    import java.awt.event.*;
    import javax.swing.*;

public class ColoredWords {
  JFrame frame;
  JPanel controlPanel, wordsPanel;
  JButton match, nomatch;

  ColoredWords() {

    SwingUtilities.invokeLater( new Runnable() {
      @Override
      public void run() {
        frame = new JFrame("Colored Words Experiment");
        wordsPanel = new JPanel();
        controlPanel = new JPanel();
        frame.setLayout(new BorderLayout());
        frame.add(wordsPanel, BorderLayout.NORTH);
        frame.add(controlPanel, BorderLayout.SOUTH);
        frame.setSize(1000, 600);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
        match = new JButton("Matching");
        nomatch = new JButton("Non-Matching");
        controlPanel.add(match, BorderLayout.WEST);
        controlPanel.add(nomatch, BorderLayout.CENTER);
        ClicksReporter clicksreporter;
        clicksreporter =  new ClicksReporter();
        match.addActionListener(clicksreporter);
        nomatch.addActionListener(clicksreporter);
      }
    } );
  }


  class ClicksReporter extends ColoredWords implements ActionListener {
    Labeling labeling = new Labeling();
    public void actionPerformed(ActionEvent e) { 
      if (e.getActionCommand().equals("Matching")) {
        wordsPanel.add(labeling);
      } else if (e.getActionCommand().equals("Non-Matching")) {
        wordsPanel.add(labeling);
      }
    }
  }


  public static void main(String[] arg) {
    new ColoredWords();
  }
}

class Labeling extends JPanel {
  JLabel[] labelsList = new JLabel[20];
  int i = 0;

  public Labeling() {
    while (i < 5) {  
      labelsList[i] =  new JLabel("black");
      setLayout(new FlowLayout(FlowLayout.CENTER, 10, 10));
      labelsList[i].setOpaque(true);
      labelsList[i].setBackground(Color.white);
      add(labelsList[i]);
      i++;
    }
  }
}

Answer 1

The problem is when you instantiate ClicksReporter inside main() . This is because it inherits the constructor of ColoredWords , calling it when instantiated. To avoid this, you can take the program code out of the constructor and into another method, say, execute() or run() . You can then adjust your program accordingly to call this method in main() .

Answer 2

Your ColoredWords constructor calls clicksreporter = new ClicksReporter(); but ClicksReporter inherits ColoredWords , so the constructor of ColoredWords gets called, wich will again execute clicksreporter = new ClicksReporter(); and so on... You get stuck in an infinite loop. Try to remove inheritance.

Answer 3

1. You create a new JFrame in your ColoredWords constructor.
2. You create a new ClicksReporter in your ColoredWords constructor.
3. ClicksReporter extends ColoredWords .

That means every ColoredWords construction leads to another ColoredWords construction, which also creates a JFrame .