Robot only runs when you tell it to run a command such as keyPress. If you don’t tell it to run a command, it uses no CPU, so there’s no need to remove the Robot object from memory. You just need to ensure that it doesn’t keep running commands continuously, in some kind of loop.

To simulate an ESCAPE key press, run robot.keyPress(java.awt.event.KeyEvent.VK_ESCAPE);
robot.keyRelease(java.awt.event.KeyEvent.VK_ESCAPE); in your Matlab code.

Instead of simulating an ESCAPE key-press, you can also simulate a mouse-up event: robot.mouseRelease(java.awt.event.InputEvent.BUTTON1_MASK);

You can also directly call the Figure’s WindowButtonUpFcn callback function to invoke imfreehand’s exit method without needing to use Robot: hFig.WindowButtonUpFcn(hFig,[])

I figured it out eventually. To my knowledge this is the only public example: https://octave.discourse.group/t/help-on-java-keyevent/2163/14

robot   = javaObject("java.awt.Robot");
wait1   = robot.delay(500);
VKeight = java_get ('java.awt.event.KeyEvent','VK_8');
a1      = javaMethod ('keyPress', robot, VKeight);
a2      = javaMethod ('keyRelease', robot, VKeight); 

etc…

The original post got me up and running in no time. Thank you so much!
I have been trying to translate what I did in Octave to share the code with others but I can’t get it to work.

Would anyone be gracious enough to give it a try?

Here is the code that behaves as I’d like it to:
Open external program, return to Octave script, Octave makes some keyboard inputs closes the program, then back to Octave to finish the remaining commands of the script

clear all
close all
clc

if exist('OCTAVE_VERSION', 'builtin') == 0
 % Matlab version   
        import java.awt.*;
        import java.awt.event.*;

        system('"calc.exe"&');

        R2D2 = Robot;
        R2D2.delay(100) 
        R2D2.keyPress(KeyEvent.VK_8)
        R2D2.keyRelease(KeyEvent.VK_8)
        R2D2.delay(500)  
    %     R2D2.keyPress(KeyEvent.VK_PLUS) % does not work!
    %    R2D2.keyRelease(KeyEvent.VK_PLUS) 
        R2D2.keyPress(KeyEvent.VK_DIVIDE)
        R2D2.keyRelease(KeyEvent.VK_DIVIDE)
        R2D2.delay(500) 
        R2D2.keyPress(KeyEvent.VK_2)
        R2D2.keyRelease(KeyEvent.VK_2)
        R2D2.delay(500) 
        R2D2.keyPress(KeyEvent.VK_ENTER)
        R2D2.keyRelease(KeyEvent.VK_ENTER)
        R2D2.delay(1000) 
        R2D2.keyPress(KeyEvent.VK_ALT)
        R2D2.keyPress(KeyEvent.VK_F4)
        R2D2.keyRelease(KeyEvent.VK_ALT)
        R2D2.keyRelease(KeyEvent.VK_F4)
      else
% Octave Version not working 
% OBJ = java_set (OBJ, NAME, VAL)
% obj = javaObject (classname, arg1, …)
% Ret = javaMethod (methodname, obj, arg1, …)  
% There is no import function so we need to express the full qualifier
% https://savannah.gnu.org/task/?12601

        system("calc.exe", false, "async"); 

        R2D2 = javaObject("java.awt.Robot"); % works
        R2D2.delay(5000); % works
%        R2D2.keyPress(KeyEvent.VK_8)
%        javaMethod('KeyPress', R2D2, VK_ENTER)
%        javaMethod("KeyRelease", R2D2, 'VK_8')  
%        javaMethod('KeyPress', 'VK_ENTER')
%        R2D2.keyRelease(KeyEvent.VK_8)
  
%        R2D2.delay(500); 
%       javaMethod('KeyPress', R2D2, VK_PLUS)
%        javaMethod('KeyRelease', R2D2, VK_PLUS)
%        R2D2.delay(500); 
%        javaMethod('KeyPress', R2D2, VK_2)
%        javaMethod('KeyRelease', R2D2, VK_2)
%        R2D2.delay(500); 
%       javaMethod('KeyPress', R2D2, VK_ENTER)
%        javaMethod('KeyRelease', R2D2, VK_ENTER)
%      1+2
        
end

The reason why I am interested can we found here: Acoustic Horn Design – The Easy Way (Ath4) | Page 459 | diyAudio)
We are trying to perform some optimization on the design of an DIY acoustic waveguide.
Any help would be much appreciated!

a = input('Type a word: ', 's');

This is for the purpose of testing the interactive feature of a program. Is it possible?

Thanks!

create an int[] array for all the KeyEvent.Vk_1 to ..last then use the for loop to iterate over the same.

@Apostolos – the code as you wrote it just simulates pressing the <Enter> key so the key event will be sent to the currently-active window. If your editor is currently in focus then obviously the key event will be sent to it. If you want to send the key event to another window you must first ensure that the focus is on that window. There is no general way to do this, it is application-dependent.

system('w0315v11-64bit');
robot = java.awt.Robot;
robot.keyPress  (java.awt.event.KeyEvent.VK_ENTER);
robot.keyRelease(java.awt.event.KeyEvent.VK_ENTER); 

But instead of pressing enter on the programs window it presses it in the Matlab editor.
Can you please tell me how to overcome this?
Thank you in advance