i glad to see that  you reply.
if you  know  c-style syntax rasters[] , please tell me  ,too.

thanks to cylab.

this is all codes of  a test programme as follows:

public class drawf
        extends glskeleton
        implements GLEventListener
        , KeyListener
{
   private byte rasters2[]=new byte[]
         {(byte)0xff,(byte)0xff,(byte)0xc0,(byte)0xc0,(byte)0xc0,(byte)0xff,
         (byte)0xff,(byte)0xc0,(byte)0xc0,(byte)0xc0,(byte)0xff,(byte)0xff};

   
    private byte rasters[] = new byte[] { (byte) 0xc0, (byte) 0x00,
            (byte) 0xc0, (byte) 0x00, (byte) 0xc0, (byte) 0x00, (byte) 0xc0,
            (byte) 0x00, (byte) 0xc0, (byte) 0x00, (byte) 0xff, (byte) 0x00,
            (byte) 0xff, (byte) 0x00, (byte) 0xc0, (byte) 0x00, (byte) 0xc0,
            (byte) 0x00, (byte) 0xc0, (byte) 0x00, (byte) 0xff, (byte) 0xc0,
            (byte) 0xff, (byte) 0xc0 };

    //
    public drawf() {
    }

    public static void main(String[] args) {
        GLCapabilities caps = new GLCapabilities();
        GLJPanel canvas = new GLJPanel(caps);
        drawf demo = new drawf();
        canvas.addGLEventListener(demo);
        demo.setCanvas(canvas);
        demo.setDefaultListeners(demo);

//        JFrame.setDefaultLookAndFeelDecorated(true);
        JFrame frame = new JFrame("drawf");
        frame.setSize(500, 500);
        frame.setLocationRelativeTo(null);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        frame.getContentPane().add(canvas);
        frame.setVisible(true);
        canvas.requestFocusInWindow();
       
    }

    public void init(GLAutoDrawable drawable) {
        GL gl = drawable.getGL();
        //
        gl.glPixelStorei(GL.GL_UNPACK_ALIGNMENT, 1);
        gl.glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
    }

    public void display(GLAutoDrawable drawable) {
        GL gl = drawable.getGL();
        GLUT glut = new GLUT();
        //
        gl.glClear(GL.GL_COLOR_BUFFER_BIT);
        gl.glColor3f(1.0f, 1.0f, 1.0f);
        gl.glRasterPos2f(50.5f,20.5f);
        //绘制4个字符
//        gl.glBitmap(10, 12, 0.0f, 0.0f, 12.0f, 0.0f, rasters, 0);
//        gl.glBitmap(10, 12, 0.0f, 0.0f, 12.0f, 0.0f, rasters, 0);
//        gl.glBitmap(10, 12, 0.0f, 0.0f, 12.0f, 0.0f, rasters, 0);
//        gl.glBitmap(10,12,0.0f,0.0f,14.0f,0.0f,rasters2,0);
        glut.glutBitmapString(GLUT.BITMAP_HELVETICA_18, "Hello world");
        gl.glFlush();
    }

    public void reshape(GLAutoDrawable drawable, int x, int y, int w, int h) {
        GL gl = drawable.getGL();
        //
        gl.glViewport(0, 0, w, h);
        gl.glMatrixMode(GL.GL_PROJECTION);
        gl.glLoadIdentity();
        gl.glOrtho(0, w, 0, h, -1.0, 1.0);
        gl.glMatrixMode(GL.GL_MODELVIEW);
    }

    public void displayChanged(GLAutoDrawable drawable, boolean modeChanged,
            boolean deviceChanged) {
    }

    public void keyTyped(KeyEvent key) {
        // TODO Auto-generated method stub
    }

    public void keyPressed(KeyEvent key) {
        switch (key.getKeyChar()) {
        case KeyEvent.VK_ESCAPE:
            System.exit(0);
            break;

        default:
            break;
        }
    }

    public void keyReleased(KeyEvent key) {
        // TODO Auto-generated method stub
    }

}

I don't know   how "rasters" is  used ?  I see some codes   look like this array . question is how  " rasters" comes?

I have a question,
  this is a piece of programmes as follows:
   private byte rasters[] = new byte[] { (byte) 0xc0, (byte) 0x00,
            (byte) 0xc0, (byte) 0x00, (byte) 0xc0, (byte) 0x00, (byte) 0xc0,
            (byte) 0x00, (byte) 0xc0, (byte) 0x00, (byte) 0xff, (byte) 0x00,
            (byte) 0xff, (byte) 0x00, (byte) 0xc0, (byte) 0x00, (byte) 0xc0,
            (byte) 0x00, (byte) 0xc0, (byte) 0x00, (byte) 0xff, (byte) 0xc0,
            (byte) 0xff, (byte) 0xc0 };
 display(){
      gl.glBitmap(10, 12, 0.0f, 0.0f, 12.0f, 0.0f, rasters, 0);
       gl.glBitmap(10, 12, 0.0f, 0.0f, 12.0f, 0.0f, rasters, 0);
      gl.glBitmap(10, 12, 0.0f, 0.0f, 12.0f, 0.0f, rasters, 0);
gl.glflush();
}
as a result of it . three 'f' is printed on the screen.
I don't  know how rasters array is setted?

who know ?
thanks