Image in java

Question

hai,
i have written this small code to generate image on the fly. But the images saved are always showing only black screen with out anythinh on them. can you pleaes explain me why its happening?
this is my code
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.util.Random;
import java.io.*;
import java.awt.image.*;
import com.sun.image.codec.jpeg.*;
public class imageserver extends JFrame{
public String Generate()
          int r,g,b;
          String query;
BufferedImage buffer = new BufferedImage (375, 250, BufferedImage.TYPE_INT_RGB );
Graphics2D img = buffer.createGraphics();
JPEGImageEncoder encoder = null;
          //get new random numbers less than 255 for red r,green g and blue b
          r = 1 + (int) ( Math.random() * 255 );
          g = 1 + (int) ( Math.random() * 255 );
          b = 1 + (int) ( Math.random() * 255 );
//get random string of four characters; to prepare the puzzle string
          query = RndString(4);
//draw image in memory
          //set new random drawing color
          img.setColor(new Color(r,g,b));
//draw the string generated on to the buffered image
img.drawString( query, 390, 260 );
img.drawRect(380,300,420,320);
try {
encoder = JPEGCodec.createJPEGEncoder (new FileOutputStream ("test.jpeg"), JPEGCodec.getDefaultJPEGEncodeParam( buffer ));
encoder.encode( buffer);
catch(Exception e){ }
return(query);
     public static String RndString (int length)
          StringBuffer sb = new StringBuffer();
          for (int i = 0; i < length;i++)
               sb.append( (char) (65 + (int) ( Math.random() * (90-65))));
          return sb.toString();
     public static void main( String args[])
imageserver imagefile = new imageserver();
System.out.println(imagefile.Generate());
Thankyou.
:-(

Answer 1

It looks like you're painting your text and rectangle outside the range of your buffer. Try reducing the x,y coordinates of each and it should work fine. Good luck!
-Chris