import java.awt.Color;
import java.awt.Container;
import java.awt.GridLayout;

import javax.swing.JFrame;
import javax.swing.JPanel;

public class JPanelExample {

	public static void main(String[] args) {

		int n = 50;

		JFrame frame = new JFrame();
		Container cp = frame.getContentPane();
		JPanel jpanel = new JPanel(new GridLayout(n, 1));
		cp.add(jpanel);

		long time = System.currentTimeMillis();

		for (int i = 0; i < n; ++i) {
			JPanel jpanel_1 = new JPanel(new GridLayout(1, n));
			jpanel.add(jpanel_1);
			for (int j = 0; j < n; ++j) {
				switch ((i * n + j) % 3) {
				case 0:
					JPanel inner = new JPanel();
					inner.setBackground(Color.red);
					jpanel_1.add(inner);
					break;
				case 1:
					JPanel inner2 = new JPanel();
					inner2.setBackground(Color.green);
					jpanel_1.add(inner2);
					break;
				case 2:
					JPanel inner3 = new JPanel();
					inner3.setBackground(Color.blue);
					jpanel_1.add(inner3);
					break;
				}
			}
		}

		System.out.println("time1=" + (System.currentTimeMillis() - time)); //$NON-NLS-1$

		frame.pack();
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.setVisible(true);
		System.out.println("time2=" + (System.currentTimeMillis() - time)); //$NON-NLS-1$

	}
}

package swtview;

import org.eclipse.swt.SWT;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;

public class Gridtest {

	public static void main(String[] args) {
		Display display = new Display();
		final Shell shell = new Shell(display);

		/**
		 * Here the number of elements in a row or column. Adjust this integer
		 * to increase the impact.
		 */
		int n = 50;
		shell.setBackground(display.getSystemColor(SWT.COLOR_WHITE));
		GridLayout layout = new GridLayout(1, true);
		layout.horizontalSpacing = 0;
		layout.verticalSpacing = 0;
		layout.marginHeight = 0;
		layout.marginWidth = 0;
		shell.setLayout(layout);

		long time = System.currentTimeMillis();

		for (int i = 0; i < n; i++) {
			Composite row = new Composite(shell, SWT.NONE);
			GridLayout layout1 = new GridLayout(n, true);
			layout1.horizontalSpacing = 0;
			layout1.verticalSpacing = 0;
			layout1.marginHeight = 0;
			layout1.marginWidth = 0;
			row.setLayout(layout1);
			GridData data = new GridData(SWT.LEFT, SWT.TOP, true, true);
			row.setLayoutData(data);
			for (int j = 0; j < n; j++) {
				GridData data1 = new GridData(SWT.LEFT, SWT.TOP, true, true);
				switch ((i * n + j) % 3) {
				case 0:
					Composite inner = new Composite(row, SWT.NONE);
					inner.setBackground(display.getSystemColor(SWT.COLOR_RED));
					inner.setLayoutData(data1);
					break;
				case 1:
					Composite inner2 = new Composite(row, SWT.NONE);
					inner2.setBackground(display.getSystemColor(SWT.COLOR_GREEN));
					inner2.setLayoutData(data1);
					break;
				case 2:
					Composite inner3 = new Composite(row, SWT.NONE);
					inner3.setBackground(display.getSystemColor(SWT.COLOR_BLUE));
					inner3.setLayoutData(data1);
					break;
				}

			}
		}

		System.out.println("time1=" + (System.currentTimeMillis() - time)); //$NON-NLS-1$

		shell.pack();
		shell.setSize(800, 600);
		shell.open();

		System.out.println("time2=" + (System.currentTimeMillis() - time)); //$NON-NLS-1$
		while (!shell.isDisposed()) {
			if (!display.readAndDispatch()) {
				display.sleep();
			}
		}

		display.dispose();
	}

}