Class Method NullPointerException <p>I have an</p> <pre><code>public abstract class Entity { public Entity() {} public void update() { this.x = 0; this.y = 0; } } </code></pre> <p>then I have a </p> <pre><code>public class Player Extends Entity { /* Class Definition */ } </code></pre> <p>when i call player.update</p> <p>I get a NullPointerException:</p> <pre><code>Exception in thread "main" java.lang.NullPointerException at MainFrame.Gui.&lt;init&gt;(Gui.java:29) at Start.main(Start.java:13) </code></pre>