To find out if an object has collided with another you can use the method that is present in all classes.

					//Returns true if there was a collision, otherwise, returns false.
					public boolean collided(GameObject);
				

Also, it is possible to check if there was a collision by using the static class Collision, with the method

					boolean collided(GameObject obj1, GameObject obj2);
				

Example:

					if( Collision.collided(barcoAmarelo, barcoVermelho) == true)
						print("collided"); 
				

The collision class can be used to check collision between any of the objects: GameObject, GameImage, Animation and Sprite.

Example: Checking for collisions between objects.

					package Collision001;

					import jplay.Animation;
					import jplay.GameImage;
					import jplay.Window;
					import jplay.Sprite;

					/**
					 * @author Gefersom Cardoso Lima
					 * Federal Fluminense University
					 * Computer Science
					 */

					public class Colision001
					{
						//At the time the bird colliding with the rock it explodes
						public static void main(String[] args)
						{
								Window window = new Window(800,600);

								GameImage stone = new GameImage("stone.png");
								stone.x = 396;
								stone.y = 63;
								
								GameImage sky = new GameImage("sky.png");
								Sprite bird = new Sprite("bird.png", 3);
								bird.setTotalDuration(360);

								Animation explosion = new Animation("explosion.png",20);
								explosion.setTotalDuration(1400);            
								explosion.setLoop(false);//The animation will run only once.

								bird.x = 100;
								bird.y = 460;

								boolean collided = false;
								while(true)
								{
										sky.draw();
										stone.draw();

										if (collided == false)
										{
											bird.draw();
											bird.update();
											bird.moveTo(600, bird.y, 0.8);
											if (bird.collided(stone))
											{
												collided = true;
												System.out.println(explosion.width);
												explosion.x = bird.x - 70;
												explosion.y = bird.y - 50;
											}
										}
										else
										{
											explosion.update();
											explosion.draw();
										}

										if (explosion.isPlaying() == false && collided == true)
											explosion.hide();

										window.update();
										window.delay(10);
								}
						}
					}