How to set border on jPanel?

Question

My projects constists of two classes, GoBoard extends JPanel.

GoTest.java:

import javax.swing.*;
import java.awt.Graphics;
import java.io.*;
import java.awt.*;

import javax.swing.border.Border;
import javax.swing.border.LineBorder;

class GoTest{
    private static void initGui(){
        JFrame frame = new JFrame("GoBoard");
        GoBoard jboard = new GoBoard();
        jboard.setLayout(new BorderLayout(10,10));
        jboard.setBorder(BorderFactory.createEmptyBorder(0,10,10,10)); 
        frame.add(jboard);



        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(400, 400);
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args){
        javax.swing.SwingUtilities.invokeLater(new Runnable(){
            public void run(){
                initGui();
            }
        });
    }
}

GoBoard.java:

import javax.swing.*;
import java.awt.Graphics;
import javax.swing.border.Border;
class GoBoard extends JPanel{
    private int linien;

    public GoBoard(){
        this(9);    
    }

    public GoBoard(int pLinien){
        this.linien = pLinien;
        this.setBorder(BorderFactory.createEmptyBorder(0,10,10,10)); 
    }

    public void paintComponent(Graphics g){
        super.paintComponent(g);
        int d = 0;
        int h = 0;
        for(int i = 0; i < this.linien; i++){
            g.drawLine(0,h, getWidth(), h);
            g.drawLine(d,0,d,getHeight());
            h += getHeight()/this.linien;
            d +=getWidth()/this.linien;
        }
    }
}

I want to set a border to have padding according to the frame where I display the panel. However I get no border. Any idea?

Answer 1

JPanel jPanel = new JPanel();

jPanel.setBorder(BorderFactory.createLineBorder(Color.black));

Here not only jPanel, you can add border to any Jcomponent