I can reproduce the bug on Redhat 7.1 and 6.1 using JRE 1.3.1, 1.3.0_03.
Didn't try RH 6.2 and other JREs.

The following are two small programs:

closewin is the main roboot program I used for automation.
=======================================================================
/* Copyright (c) 1999 by Sun Microsystems, Inc.
 * All rights reserved.

 * ident %Z%%M% %I% %E%

 * This code is provided "AS IS", without any warranty of any kind.
 * Sun is under no obligation to provide maintenance or support for
 * this code or provide future updates thereto.

 * SUN DOES NOT MAKE AND HEREBY DISCLAIMS ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING BUT NOT LIMITED TO, WARRANTIES OF NON-
 * INFRINGEMENT, MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE,
 * OR ANY WARRANTIES ARISING FROM A COURSE OF DEALING, USAGE OR TRADE
 * PRACTICE.
 */


import java.awt.*;
import java.awt.event.*;
import java.awt.Robot.*;
import java.util.Vector;

public class closewin {
    Robot rob;
    int elapse = 20;
    int [] keySequence = new int[10];
    int totalKeys = 0;
    
    public static void main(String [] args) {
closewin c = new closewin();
c.run(args);
    }
    
    /**
     * Arguments:
     * 1. None: Wait default 20 seconds and press/release enter key
     * 2. [Time in seconds] [key sequence]
     * e.g.
     * 20
     * 20 ALT S
     * I am limiting the key press sequece to 10. It will be rare if
     * you want to press more than 4 keys all together!
     */
    public void run (String [] args) {
if ( args.length > 0 ) {
elapse = Integer.parseInt(args[0]);
}
if (args.length > 1) {
processKeySequence(args);
totalKeys = args.length - 1;
} else {
keySequence[0] = KeyEvent.VK_ENTER;
totalKeys = 1;
}


try {
rob = new Robot();
} catch (Exception e) {
System.out.println("Error in loading Robot!" + e.toString());
System.exit(-1);
}

try {
for(int i = elapse; i > 0; i--) {
// System.out.println("Time to close window in " + i + " seconds");
Thread.sleep(1000);
}
} catch (InterruptedException e) {}


for (int i = 0; i < totalKeys; i++) {
System.out.println("Pressing key " + keySequence[i]);
rob.keyPress(keySequence[i]);
}
// for (int i = totalKeys - 1; i >= 0; i--) {
for (int i = 0; i < totalKeys; i++) {
System.out.println("Releasing key " + keySequence[i]);
rob.keyRelease(keySequence[i]);
}

System.exit(0);
    }

    private void processKeySequence(String [] args) {
// The args[0] is second number
for (int i = 0; i < args.length - 1; i++) {
// Not implemented for all keys. For JWS test only here.
if (args[i+1].equals("ALT")) {
keySequence[i] = KeyEvent.VK_ALT;
} else if (args[i+1].equals("S")) {
keySequence[i] = KeyEvent.VK_S;
} else {
keySequence[i] = KeyEvent.VK_ENTER;
}
}
    }

}



RobotBug is the small program used to demonstrate the problem. [Notice that there is no invocation of java.awt.Robot in this test!!!]
======================================================================
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

class RobotBug {
    public static void main(String [] args) {
RobotBug r = new RobotBug();
    }

    RobotBug () {
JFrame f = new JFrame ();
Container c = f.getContentPane();

JButton b = new JButton("Alt+S for activation");
b.setMnemonic(KeyEvent.VK_S);
b.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.exit(0);
}
}
);

c.add(b);

f.pack();
f.show();

    }

}



The steps to run them is:
1. Run command:
java closewin 20 ALT S &
(ALT+S key will be pressed after 20 seconds.)
2. Run command:
java RobotBug

After a while, the RobotBug program will exit since Alt+S key is pressed.
(The RobotBug program has the focus.)

The above two program works on Solaris, Windows, but not on Linux.

Note the commented line in closewin.java:
// for (int i = totalKeys - 1; i >= 0; i--) {

I tried both release sequences, i.e. release last pressed key first, or
release first pressed key first, none of them worked.

nathan.wang@Eng 2001-07-10