JOGL test for OffScreen buffer

package jogltest;

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;
import javax.media.opengl.GL2;
import javax.media.opengl.GLCapabilities;
import javax.media.opengl.GLContext;
import javax.media.opengl.GLDrawableFactory;
import javax.media.opengl.GLOffscreenAutoDrawable;
import javax.media.opengl.GLProfile;

import com.jogamp.opengl.util.awt.AWTGLReadBufferUtil;

public class TestOffScreen {

    public static void main(String[] args) {

        GL2 gl2;

        GLDrawableFactory fac = GLDrawableFactory.getFactory(GLProfile.getDefault());
        GLCapabilities glCap = new GLCapabilities(GLProfile.getDefault());
        // Without line below, there is an error on Windows.
        glCap.setDoubleBuffered(false);
        //makes a new buffer 100x100
        GLOffscreenAutoDrawable buf = fac.createOffscreenAutoDrawable(null, glCap, null, 100, 100);
        GLContext context =  buf.createContext(null);
        context.makeCurrent();
        gl2 = context.getGL().getGL2();
        gl2.glViewport(0, 0, 100, 100);
        gl2.glShadeModel(GL2.GL_SMOOTH);
        gl2.glClearColor(1.0f, 0.80f, 0.80f, 1);    // This Will Clear The Background Color
        gl2.glClearDepth(1.0);                    // Enables Clearing Of The Depth Buffer
        gl2.glClear(GL2.GL_COLOR_BUFFER_BIT | GL2.GL_DEPTH_BUFFER_BIT);
        gl2.glLoadIdentity();                    // Reset The Projection Matrix
        AWTGLReadBufferUtil agb = new AWTGLReadBufferUtil(buf.getGLProfile(), true);
        BufferedImage image = agb.readPixelsToBufferedImage(context.getGL(), true);
        try {
            ImageIO.write(image, "PNG", new File("test.png"));
        } catch (IOException e) {
            e.printStackTrace();
        }
        context.destroy();
        buf.destroy();
        System.out.println("Done!");
    }

}