Tugas Java Gridbag Layout

import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import javax.swing.*;
public class GridBagku extends JFrame{
JButton b1,b2,b3,b5,b6,b7,b8,b9,b10,b11;

public GridBagku() {
setTitle("Grid Bag");
b1=new JButton("B1");
b2=new JButton("B2");
b3=new JButton("B3");
b5=new JButton("B5");
b6=new JButton("B6");
b7=new JButton("B7");
b8=new JButton("B8");
b9=new JButton("B9");
b10=new JButton("B10");
b11=new JButton("B11");

GridBagConstraints gbc=new GridBagConstraints();
setLayout(new GridBagLayout());
gbc.insets=new Insets(5, 5, 5, 5);
gbc.fill=GridBagConstraints.BOTH;
gbc.gridx=0;
gbc.gridy=0;
gbc.gridwidth=1;
add(b1,gbc);
gbc.gridx=0;
gbc.gridy=1;
gbc.gridwidth=1;
add(b2,gbc);
gbc.gridx=0;
gbc.gridy=2;
gbc.gridwidth=1;
add(b3,gbc);
gbc.gridx=1;
gbc.gridy=0;
gbc.gridheight=3;
gbc.gridwidth=2;
gbc.gridx=3;
gbc.gridy=0;
gbc.gridheight=1;
add(b5,gbc);
gbc.gridx=3;
gbc.gridy=1;
gbc.gridheight=2;
add(b6,gbc);
gbc.gridx=0;
gbc.gridy=3;
gbc.gridwidth=6;
gbc.gridheight=1;
add(b7,gbc);
gbc.gridx=0;
gbc.gridy=4;
gbc.gridwidth=1;
add(b8,gbc);
gbc.gridx=1;
gbc.gridy=4;
gbc.gridwidth=1;
add(b9,gbc);
gbc.gridx=2;
gbc.gridy=4;
gbc.gridwidth=1;
add(b10,gbc);
gbc.gridx=3;
gbc.gridy=4;
gbc.gridwidth=1;
add(b11,gbc);

setSize(270, 240);

setDefaultCloseOperation(3);

}

public static void main(String[] args) {

new GridBagku().setVisible(true);

}

}

Output :