That's too bad.  Did you have a question,
or were you just after sympathy**?

If the former, you might try posting a short,
compilable example* that would explain things
like..
- what is location, when is it updated and by what?
-   "   "  width     "   "  "    "      "   "  "?
-   "   "  height    "   "  "    "      "   "  "?
- ..

* More specifically, an SSCCE is generally the
preferred way to express that.
<http://www.physci.org/codes/sscce.html>

** Oh, and if the latter.
'There there.. there there'

Andrew T.

There is some lack of information about dx,dy:
   can they be >1  (fast moves) ?
   can they be <1  (slow move, or purely horizontal/vertical move)
   can they be anything between 0 and 1 ?   (type double or int?)

If they can be anything else than 1 or -1, then you might run
into the problem that just reversing the direction fails to move
the ball back inside the bounds. (for that to really happen,
there must be some more places that modify speed or position,
but I find it quite likely that this happens, or the balls
trajectory would be quite boring)
Once the ball is "out", and reversing the direction doesn't bring
it "in" immediately, it will toggle direction every time, and it's
a question of mere luck whether it gets back "in" any time at all.

    if (location.x <= 1) {
           if (dx<0) dx=-dx;
           location.x=1-location.x;
       }
    if (location.x >= (width-1) ) {
           if (dx>0) dx=-dx;
           location.x=2*(width-1)-location.x;
       }

And analogously for "y".  if your dx,dy are ints you might need
casts for the Math.abs()...  or you just throw in a second "if":
if (dx<0) dx=-dx;  

PS: the bounds of your field look asymmetric:
 if the field is exactly "width" positions wide, then
 the valid indices are  0..(width-1)   You cut the left
 edge, but don't cut the right edge.
 If this is on purpose, then it's fine, otherwise it my be some bug.

Perhaps this code doesn't work because you haven't defined a class, a
main method, etc?
(Hint: try actually asking a question and stating what your actually
problem is apart from "does not work".)

[snip]

Bellow follows a complete working example with model, view and
controller components.

Pay attention to the OO design implemented.

If I may, I would also suggest a very good book to begin with: D.
Schmidt, Programming principles in Java -- architectures and
interfaces, which can be obtained for free at the following site:

http://www.cis.ksu.edu/santos/schmidt/ppj

Regards,
Faton Berisha

public class MovingBall
{ private int xPos;
 private int yPos;
 private int radius;
 private int xVelocity = 5;
 private int yVelocity = 2;
 private Box container;

 public MovingBall(int xInit, int yInit, int r, Box box)
 { xPos = xInit;
   yPos = yInit;
   radius = r;
   container = box;
 }

 public int xPosition()
 { return xPos; }

 public int yPosition()
 { return yPos; }

 public int radiusOf()
 { return radius; }

 public void move()
 { xPos = xPos + xVelocity;
   if ( container.inHorizontalContact(xPos) )
   { xVelocity = -xVelocity; }
   yPos = yPos + yVelocity;
   if ( container.inVerticalContact(yPos) )
   { yVelocity = -yVelocity; }
 }
}

public class Box
{ private int boxSize;
 public Box(int size)
 { boxSize = size; }

 public boolean inHorizontalContact(int xPosition)
 { return xPosition <= 0 || xPosition >= boxSize; }

 public boolean inVerticalContact(int yPosition)
 { return yPosition <= 0 || yPosition >= boxSize; }

 public int sizeOf()
 { return boxSize; }
}

import java.awt.*;
public class BallWriter
{ private MovingBall ball;
 private Color color;

 public BallWriter(MovingBall b, Color c)
 { ball = b;
   color = c;
 }

 public void paint(Graphics g)
 { g.setColor(color);
   int radius = ball.radiusOf();
   g.fillOval(ball.xPosition() - radius,
     ball.yPosition() - radius, 2 * radius, 2 * radius);
 }
}

import java.awt.*;
public class BoxWriter
{ private Box box;

 public BoxWriter(Box b)
 { box = b; }

 public void paint(Graphics g)
 { int size = box.sizeOf();
   g.setColor(Color.white);
   g.fillRect(0, 0, size, size);
   g.setColor(Color.black);
   g.drawRect(0, 0, size, size);
 }
}

import javax.swing.*;
import java.awt.*;
public class AnimationWriter extends JPanel
{ private BoxWriter boxWriter;
 private BallWriter ballWriter;

 public AnimationWriter(BoxWriter bx, BallWriter bl, int size)
 { boxWriter = bx;
   ballWriter = bl;
   JFrame f = new JFrame();
   f.getContentPane().add(this);
   f.setTitle("Topi kërcyes");
   f.setSize(size, size);
   f.setVisible(true);
 }

 public void paintComponent(Graphics g)
 { boxWriter.paint(g);
   ballWriter.paint(g);
 }
}

public class BounceController
{ private MovingBall ball;
 private AnimationWriter writer;

 public BounceController(MovingBall b, AnimationWriter w)
 { ball = b;
   writer = w;
 }

 public void runAnimation()
 { while ( true )
   { delay(20);
     ball.move();
     writer.repaint();
   }
 }

 private void delay(int milisecs)
 { try { Thread.sleep(milisecs); }
   catch (InterruptedException e) { }
 }
}

import java.awt.*;
public class TestBouncingBall
{ public static void main(String[] args)
 { int boxSize = 200;
   int ballRadius = 6;
   Box box = new Box(boxSize);
   MovingBall ball = new MovingBall(boxSize / 3, boxSize / 5,
     ballRadius, box);
   BallWriter ballWriter = new BallWriter(ball, Color.red);
   BoxWriter boxWriter = new BoxWriter(box);
   AnimationWriter writer = new AnimationWriter(boxWriter,
     ballWriter, boxSize);
   new BounceController(ball, writer).runAnimation();
 }
}