If we plug the controller to an object myObject containing a 'property' field and enable this controller to listen to changes of 'property' :

cp5 = new ControlP5(this) cp5.addSlider("property").plugTo(myObject).listen(true);

We get :

java.lang.NoSuchFieldException: separation java.lang.NullPointerException at processing.mode.java.runner.Runner.findException(Runner.java:947) at processing.mode.java.runner.Runner.reportException(Runner.java:892) at processing.mode.java.runner.Runner.exceptionEvent(Runner.java:818) at processing.mode.java.runner.Runner$2.run(Runner.java:707)

It seems the listen method is looking for a field named 'property' in the context controlP5 was created in, whereas it should now be looking for the field 'property' in myObject.