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javaeclipseappletprocessing

Java error: cannot cast to java.applet.Applet in Eclipse

So here is really simple code that will not compile in Eclipse:

import processing.core.*;

public class MyPApplet extends PApplet {
}

I'm trying to run it as a Java Applet, but I get the error: 

java.lang.ClassCastException: MyPApplet cannot be cast to java.applet.Applet

The problem is PApplet is a class from processing package, and it extends java.applet.Applet, and MyPApplet extends PApplet, but I still get this error. It makes no sense. Why can't MyPApplet be cast to java.applet.Applet?

Can someone please help?

Solution

  • Like George said, PApplet no longer extends Applet as of Processing 3.

    But instead of going back to an old version of Processing, I would recommend using the runSketch() function to run your sketch:

    public class MyPapplet extends PApplet {

  public static void main(String... args){
    String[] pArgs = {"MyPapplet "};
    MyPapplet mp = new MyPapplet ();
    PApplet.runSketch(pArgs, mp);
  }

  public void settings() {
    size(200, 100);
  }
  public void draw() {
    background(255);
    fill(0);
    ellipse(100, 50, 10, 10);
  }
}

    If you really need access to the underlying native component, you have to write code that depends on what renderer you're using. Here's how you'd do it with the default renderer:

    PSurfaceAWT awtSurface = (PSurfaceAWT)mp.surface;
PSurfaceAWT.SmoothCanvas smoothCanvas = (PSurfaceAWT.SmoothCanvas)awtSurface.getNative();

    But the first approach should be good enough for most people, so try that first.