I am having a Null pointer exception in line 66.

It looks like you only create line objects for all positions in lines except the last one.

So when you reach the end of the array, you get a null pointer exception, although it wouldn't be on the line you indicated.

When you post code, please wrap it in [code][/code] tags so it's legible. Also when you get an exception, post the stack trace as well.

paulcwa at 2007-7-8 21:58:07 >

thanks paulcw ;

After playing with the code a bit I finally got the program behaving properly.

I just wanted to say thanks for the help.

here is what I finally went with.

import java.awt.Color;

import java.awt.Graphics;

import java.util.Random;

import javax.swing.JPanel;

public class DrawPanel1 extends JPanel

{

private Random randomNumbers = new Random();

private MyLine1 lines[]; // array on lines

private MyRect1 rects[]; // array on lines

private MyOval1 ovals[]; // array on lines

// constructor, creates a panel with random shapes

public DrawPanel1()

{

setBackground( Color.WHITE );

lines = new MyLine1[ 50 + randomNumbers.nextInt( 50 ) ];

// create lines

for ( int count = 0; count < lines.length; count++ )

{

// generate random coordinates

int x1 = randomNumbers.nextInt( 500 );

int y1 = randomNumbers.nextInt( 500 );

int x2 = randomNumbers.nextInt( 500 );

int y2 = randomNumbers.nextInt( 500 );

// generate a random color

Color color = new Color( randomNumbers.nextInt( 256 ),

randomNumbers.nextInt( 256 ), randomNumbers.nextInt( 256 ) );

// add the line to the list of lines to be displayed

lines[ count ] = new MyLine1( x1, y1, x2, y2, color );

} // end for

rects = new MyRect1[ 50 + randomNumbers.nextInt( 50 ) ];

// create lines

for ( int count = 0; count < rects.length; count++ )

{

// generate random coordinates

int x1 = randomNumbers.nextInt( 500 );

int y1 = randomNumbers.nextInt( 500 );

int x2 = randomNumbers.nextInt( 500 );

int y2 = randomNumbers.nextInt( 500 );

// generate a random color

Color color = new Color( randomNumbers.nextInt( 256 ),

randomNumbers.nextInt( 256 ), randomNumbers.nextInt( 256 ) );

Boolean filled = randomNumbers.nextBoolean();

// add the line to the list of lines to be displayed

rects[ count ] = new MyRect1( x1, y1, x2, y2, color, filled );

} // end for

ovals = new MyOval1[ 50 + randomNumbers.nextInt( 50 ) ];

// create lines

for ( int count = 0; count < ovals.length; count++ )

{

// generate random coordinates

int x1 = randomNumbers.nextInt( 500 );

int y1 = randomNumbers.nextInt( 500 );

int x2 = randomNumbers.nextInt( 500 );

int y2 = randomNumbers.nextInt( 500 );

// generate a random color

Color color = new Color( randomNumbers.nextInt( 256 ),

randomNumbers.nextInt( 256 ), randomNumbers.nextInt( 256 ) );

Boolean filled = randomNumbers.nextBoolean();

// add the line to the list of lines to be displayed

ovals[ count ] = new MyOval1( x1, y1, x2, y2, color, filled );

} // end for

} // end DrawPanel constructor

public String numShapes()

{

String statusText;

statusText = "Lines: " + lines.length + "Ovals: " + ovals.length + "Rects:" + rects.length;

return statusText;

}

// for each shape array, draw the individual shapes

public void paintComponent( Graphics g )

{

super.paintComponent( g );

// draw the lines

for ( MyLine1 line : lines )

line.draw( g );

for ( MyRect1 rect : rects )

rect.draw( g );

for ( MyOval1 oval : ovals )

oval.draw( g );

} // end method paintComponent

} // end class DrawPanel1

thanks again.ad3

ad3a at 2007-7-8 21:58:07 >