Undefined variable "modem" or class "modem.pskmod" when calling from java

I have written a code in matlab which modulate and demodulate some signals. I deploy them using deploytool and the .jar works in one application without GUI but gives me the Undefined variable "modem" or class "modem.pskmod". in an application with GUI.

Basically, what I want to know what will cause this error to occur as I have look around, I don't find much documentation on this error.

As I don't understand w开发者_StackOverflow中文版hy it work in one application but fails in another when the code I use is almost similar when calling the method.

Ok, after much testing and comparing the difference between an application WITHOUT a GUI and an application WITH a GUI. I found a solution to my problem.

As an application without a GUI run init the method from the start of the application (there is only one thread)
import matlabFunction.*;
public static void main(String[] args) {
matlabFunction test = new matlabFunction(); test.runFunction(1, lstABC.toArray());
}

But in my code with GUI I run the init method from within the JFrame (main() contain my init code) which is inside the EDT

public static void main(String[] args) { SwingUtilities.invokeLater(new Runnable() {

        public void run() {
            try {

                new main();
            } catch (Exception p) {
            }
        }
    });
}  

The error occur with the above way to init the matlab method. But if I change way of calling the init method as below, the error is solve.

public static void main(String[] args) { SwingUtilities.invokeLater(new Runnable() {

        public void run() {
            try {
                matlabFunction test = new matlabFunction();
                new main(test);
            } catch (Exception p) {
            }
        }
    });
} 

So, I believe the reason for my problem is not calling the init method from the "first" thread that starts the application.