update

src/main/java/PingPong/GamePanel.java

@@ -39,6 +39,10 @@ public class GamePanel extends JPanel implements Runnable {
     }
 
     public void checkCollision() {
+            //Reflection of Ball when it touches top and bottom edges!
+            if(collisionChecker.didTouchTopOrBottomEdge(ball.y, FRAME_HEIGHT-BALL_DIAMETER)) {
+                ball.setYDirection(-ball.yVelocity);
+            }
 
     }