glBegin(GL.GL_LINE_LOOP);
     for(int i =0; i <= 300; i++){
         double angle = 2 * Math.PI * i / 300;
         double x = Math.cos(angle);
         double y = Math.sin(angle);
         gl.glVertex2d(x,y);
     }
glEnd();

// C Implementation for drawing circle 
#include <graphics.h> 
  
//driver code 
int main() 
{ 
    // gm is Graphics mode which is 
    // a computer display mode that 
    // generates image using pixels. 
    // DETECT is a macro defined in 
    // "graphics.h" header file 
    int gd = DETECT, gm; 
  
    // initgraph initializes the 
    // graphics system by loading a 
    // graphics driver from disk 
    initgraph(&gd, &gm, ""); 
  
    // circle function 
    circle(ort_x, ort_y, en_uzak_nokta_mesafesi); 
  
    getch(); 
  
    // closegraph function closes the 
    // graphics mode and deallocates 
    // all memory allocated by 
    // graphics system . 
    closegraph(); 
  
    return 0; 
}