Hello All,
Ok, I see that I was doing wrong. I needed to:
i) wrap the event in a handle, as per the advice above
ii) change the callback to display the event’s properties

>> evt = EventTest
evt =
EventTest@5d332969
>> h = handle(evt,'Callbackproperties')
h =
	javahandle_withcallbacks.EventTest
>> set(evt,'TestEventCallback',@(h,e)disp([e.newValue e.oldValue]))
>> evt.notifyMyTest
     1     0
>> get(evt)
                    Class: [1×1 java.lang.Class]
        TestEventCallback: @(h,e)disp([e.newValue,e.oldValue])
    TestEventCallbackData: []

Thank you for your help, Yair.
Richard

With my version of
MATLAB Version 9.4 (R2018a)
My results are:

>> evt = EventTest
evt =
EventTest@71652c98
>> get(evt)
    Class: [1×1 java.lang.Class]
>> set(evt,'TestEventCallback',@(h,e)disp(h))
>> evt.notifyMyTest
	javahandle_withcallbacks.EventTest

Have I done something silly?
Thank you for your help.
Richard S-T (who owns both ‘Undocumented’ and ‘Accelerating’)

See http://undocumentedmatlab.com/blog/matlab-and-the-event-dispatch-thread-edt

Specifically the callbackOnEDTQueue at the end.

This class is really great and helpful, thanks for this !
There are however some issues with types and types checking, so I made a small refactor to adress those issues. Changes are essentially not using raw types, and some changes to the notifyMatlab(Object obj, MatlabAction action) method. Also, I split the sub interface and class in their own files.

package com.opalrt.efpgasim.gui.matlablistener;

import java.util.Vector;
import com.opalrt.efpgasim.gui.enumerations.MatlabAction;
/**
 * 
 * @author http://undocumentedmatlab.com/blog/matlab-callbacks-for-java-events
 */

public class MatlabEvent {
	
	public interface MatlabListener extends java.util.EventListener {
		void testEvent(MatlabEventObject event);
	}
	
	private Vector data = new Vector();

	public synchronized void addMatlabListener(MatlabListener lis) {
		data.addElement(lis);
	}

	public synchronized void removeMatlabListener(MatlabListener lis) {
		data.removeElement(lis);
	}
	
	public synchronized void printMatlabListener()
	{
		System.out.println(data.toString());
		for (int i = 0; i < data.size(); i++) {
			System.out.println("i = " + i + " is " + data.elementAt(i).toString());
		}
	}

	public void notifyMatlab(Object obj, MatlabAction action) {
		Vector dataCopy;
		synchronized (this) {
			dataCopy = new Vector(data);
		}

		for (int i = 0; i < dataCopy.size(); i++) {
			MatlabEventObject matlabEvent = new MatlabEventObject(this, obj, action);
			((MatlabListener) dataCopy.elementAt(i)).testEvent(matlabEvent);
		}
	}
	
	public class MatlabEventObject extends java.util.EventObject {
		private static final long serialVersionUID = 1L;
		private Object obj;
		private MatlabAction action;
		
		public MatlabEventObject(Object source, Object obj, MatlabAction action) {
			super(source);
			this.obj = obj;
			this.action = action;
		}

		public Object getObj() {
			return obj;
		}

		public void setObj(Object obj) {
			this.obj = obj;
		}

		public MatlabAction getAction() {
			return action;
		}

		public void setAction(MatlabAction action) {
			this.action = action;
		}		
	}	
}

@Yair
I just checked that “augmentedmatlab.com” domain name is still available 🙂

@Adam – if TMW linked to my blog it wouldn’t be “undocumented” Matlab any longer, would it? 🙂

@mySelf
The answer is here (http://undocumentedmatlab.com/blog/uicontrol-callbacks#memory_leak) thanks for that post. BTW, I wish Mathworks linked to your articles :).
Thanks again.

@Dims – see http://undocumentedmatlab.com/blog/matlab-callbacks-for-java-events-in-r2014a

@Tianxiao – see http://undocumentedmatlab.com/blog/matlab-callbacks-for-java-events-in-r2014a

(and thanks for the note on the dataCopy typo – I fixed it)