" we gonna have 4 holes/pocket on pool table which is not strange."
Really? I am used to the version without holes at all (French billiard), or a version with six holes (we call it American billiard).

If you have trouble, you might have tried something already, right? Perhaps show your failed attempt so we can guide you to improve it.

" it draws on the rectangle and cover it."
Well, that's how I would have drawn the holes anyway. Not enough for the covering to hide the green rectangle, though. But that's just matter of adjusting the diameters.
I am still curious to see your code.
" I hope you would be able to help me" - help, yes, certainly, but not do the job for you, as it would have little learning value (I used to code whatever what thrown at me, for learning purpose precisely, but now I have less to learn (in 2D at least) and lack time and I am wiser, perhaps...

An advise, to remain positive: use constants in your code - variables that define height and width of the pool table, and its position on the sketch. Then you can use these variables to position precisely your holes (use constant for their diameter) with simple math.
It allows to make the code more readable ("why did I used 103 there?") and to easily adjust the values later.

Hi thanks for the advice , i would show you my code if you really want to see it.
the problem i m having is when is try to draw the holes on the rectangle which is pool table
it covers all the rectangle.please have a look at it. :D


void setup()
{
  size(900,600);
  background(255);
  smooth();
  textAlign(CENTER);
  textSize(12);
}

void draw()
{       
        stroke(255,0,0);
        fill(0,155,0);
        rect(225,145,450,295);
       
       
       // fill(255);
       // ellipse(195,115,255,175);
}

Thanks in advance again. :D

3rd and 4th parameters to ellipse() are, by default, the radius. this can be changed using ellipseMode(). see the reference.

Move the background() call to the start of draw().
And just try a smaller radius...
Along with a proper ellipseMode() as advised, and using constants as I suggested, it should be relatively easy to position the ellipses on the corners.

OK, that's a little better, although I don't get why you don't make round ellipses...
Let's progress step by step:
- Clean up: add some spaces, use consistent indentation, move code where it belongs (ellipseMode will persist the whole sketch, background in setup isn't useful here), removed code we don't use yet (text) to make this message smaller...

1. void setup()
2. {
3.   size(900, 600);
4.   smooth();
5.   ellipseMode(CENTER);
6. }
7.  
8. void draw()
9. {     
10.   background(255);
11.   stroke(255, 0, 0);
12.   fill(0, 150, 0);
13.   rect(225, 145, 450, 295);
14.  
15.   fill(255);
16.   noStroke();
17.   ellipse(225, 145, 90, 85);
18. }

Same effect, but better base for improvements.
Now, let's use some constants:

1. // final makes them constants: not necessary, but safer
2. final int MARGIN_LEFT = 225;
3. final int MARGIN_TOP = 145;
4. final int TABLE_WIDTH = 450;
5. final int TABLE_HEIGHT = 295;
6. final int HOLE_SIZE = 90;
7. final int BACKGROUND = 255;
8. 
   
9. void setup()
10. {
11.   size(900, 600);
12.   smooth();
13.   ellipseMode(CENTER);
14. }
15. 
    
16. void draw()
17. {     
18.   background(BACKGROUND);
19.   stroke(255, 0, 0);
20.   fill(0, 150, 0);
21.   rect(MARGIN_LEFT, MARGIN_TOP, TABLE_WIDTH, TABLE_HEIGHT);
22.  
23.   fill(BACKGROUND);
24.   noStroke();
25.   ellipse(MARGIN_LEFT, MARGIN_TOP, HOLE_SIZE, HOLE_SIZE);
26. }

Still same effect, with much more verbose code...
But at least, we know what is going on.
Let's try to add more holes (replaces previous last three lines).

1.   fill(BACKGROUND);
2.   noStroke();
3.   ellipse(MARGIN_LEFT, MARGIN_TOP, HOLE_SIZE, HOLE_SIZE);
4.   ellipse(MARGIN_LEFT + TABLE_WIDTH, MARGIN_TOP, HOLE_SIZE, HOLE_SIZE);
5.   ellipse(MARGIN_LEFT, MARGIN_TOP + TABLE_HEIGHT, HOLE_SIZE, HOLE_SIZE);
6.   ellipse(MARGIN_LEFT + TABLE_WIDTH, MARGIN_TOP + TABLE_HEIGHT, HOLE_SIZE, HOLE_SIZE);

See how easy it was with some constants instead of magic numbers?
Now you can safely change the numbers in the constants area without breaking the whole stuff, and you let the computer to... compute values instead of you with a calculator.

I hope this will provide a good starting point.