@Francisco – this is one of those cases where you should ask MathWorks support. After all, you’re trying to use a supported Matlab functionality when you encountered this limitation. Maybe MathWorks will be able to resolve your problem. Alternatively, you could post your query on Matlab Answers. If you discover a workaround, please post it here in a follow-up comment.

I have been trying to replace matlabcontrol with the official java matlab engine but faced a problem. In my case I want to invoke a matlab function by a java class that is instantiated within matlab. However, when the class tries to access the matlab engine the following exception is thrown: Initializing MATLAB Engine API from MATLAB is not supported.

Can you confirm that the supported Matlab java interface does not allow connecting to a Matlab session where the java class was launched? This would then be a case where unfortunately the official interface does not replace matlabcontrol… Many thanks!

Ok, I see. I could figure out that it was a double[] by calling obj.getClass().getSimpleName().
Thank you very much Yair for these great posts and answering instantly!!

@Peyman – running a Java object that calls Matlab from within Matlab is an easy way to debug Java programs that will later be deployed outside Matlab.

[D means a Double array. See here and here. To get a more human-readable string (‘double[]’ in your case), use className = hObject.getClass.getCanonicalName().

What is the point of invoking matlab functions by a java-matlab connector from inside the matlab console like in all of your examples????? From inside a java class – where this all actually would make a sense – not much works as described above. I can mtEval a script but when it comes to invoking a function with input and/or return arguments, the only thing which works half way is this:

Matlab.mtEval("functionWithInputAndReturnValue(3, 5)", 1);

but it returns a java.lang.Object and when I call getClass on it, I receive [D No clue what it is and how to convert it into a nummerical value!?

Can you please help.

again this DOESN’T even compile:

Object isTrigger = new Object();
        int[] args = new int[2];
        args[0] = 3;
        args[1] = 5;
        try {
            isTrigger = Matlab.mtFeval("functionWithInputAndReturnValue", args, 1);
        } catch (Exception e) {
            e.printStackTrace();
        } 

import com.mathworks.jmi.*
...
Matlab.mtEval("someScript");
...

in the matlab console!

but I couldn’t get it run a function with input and/or output arguments, actually it doesn’t even compile because it either can’t call the function with the argument list or it can’t convert the return type (java.lang.Object) into the assignee (int) type – and won’t cast to an explicit cast. As all of your example invocations of Matlab.mtEval and Matlab.mtFeval are obviously examples run on Matlab console and not on a JVM, I was wondering if this is possible at all!!??

I have matlab 7.6.0 (2008a) and jdk/jvm 1.6.0 (both Matlab and compiler)

thx

PS: the code snippet:

import com.mathworks.jmi.*;
import java.util.LinkedList;

public class MatlabRunner implements Runnable{
    public LinkedList rrIntervals;
    
    public MatlabRunner(LinkedList list) {
        this.rrIntervals = list;
    }
    
    @Override
    public void run() {
        System.out.println("running the matlab runner...");
        long t0 = System.nanoTime();
        int isTrigger = 0;
        
        while(isTrigger == 0) {
            try {
                isTrigger = (int) Matlab.mtEval("waitTrigger(ioObj, address)", 1);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
      
        long t1 = System.nanoTime();
        long elapsedTime = (long) ((t1 - t0) / 1000);
        System.out.println("elapse time = " + elapsedTime);
           
        this.rrIntervals.remove();
        this.rrIntervals.add(elapsedTime);
    }
}

@Andrew – I fixed the MatlabControl link to its new home on GitHub

BTW, it looks like the “MatlabControl” link in the fifth paragraph is broken. It’s pointing to googlecode.com, which is defunct. Could you update the link to MatlabControl’s current home?

@Sergio – you only need R2016b if you want to use the new (documented) Matlab engine interface.

If you have R2016a or earlier you can use the undocumented JMI interface, as explained in the post above (and its followup posts).

Hello,

In relation to your last answer, is it necessary to have R2016b installed? I have R2013b so I don’t have that: matlabroot/extern/engines/java/jar/engine.jar

Is there any solution apart from installing R2016b?