import java.awt.Container;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
public class GridBagLayoutColumnSpanHORIZONTAL {
public static void main(String[] args) {
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Container pane = f.getContentPane();
pane.setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridx = 1;
gbc.gridy = GridBagConstraints.RELATIVE;
pane.add(new JButton("First row, first column"), gbc);
pane.add(new JButton("Second row"), gbc);
gbc.gridwidth = 2;
gbc.fill = GridBagConstraints.HORIZONTAL;
pane.add(new JButton("Third row, spans two columns"), gbc);
gbc.gridwidth = 1;
gbc.fill = GridBagConstraints.NONE;
gbc.gridx = GridBagConstraints.RELATIVE;
pane.add(new JButton("First row, second column"), gbc);
f.setSize(400, 300);
f.setVisible(true);
}
}