Java - JPanel is only one small pixel in the top center of my JFrame

Question

The JPanel called panel only shows up as one small red square up the top center, I have tried to set the size but it doesn't seem to do anything.

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import javax.swing.JFrame;
import javax.swing.JPanel;   

public class Draw extends JFrame{

private JPanel panel;

    public Draw() {
        super("title");
        setLayout(new FlowLayout());        
        panel = new JPanel();       
        panel.setBackground(Color.RED);
        add(panel, BorderLayout.CENTER);
    }
}

Answer 1

Try this :

File Draw.java

   package com.stackovfl;

    import java.awt.BorderLayout;
    import java.awt.Color;
    import java.awt.Dimension;
    import java.awt.FlowLayout;
    import javax.swing.JFrame;
    import javax.swing.JPanel;

    @SuppressWarnings("serial")
    class Draw extends JFrame {
    private JPanel panel;

      public Draw() {
        super("title");
        setLayout(new FlowLayout());
        panel = new JPanel();
        panel.setPreferredSize(new Dimension(200, 300));
        panel.setBackground(Color.RED);     
        add(panel, BorderLayout.CENTER);
        /* Important to get the layout to work */
        pack();     
        /* Center the window */
        setLocationRelativeTo(null);        
        /* Important if you want to see your window :) */
        setVisible(true);
        }
    }

File Test.java (main method to launch the window) : package com.stackovfl;

import javax.swing.SwingUtilities;

public class Test {
public static void main(String[] args) {
    SwingUtilities.invokeLater(new Runnable() {
        @Override
        public void run() {
            new Draw();
        }
    });
   }
}