java.awt.Robot atomic operation (KeyPress + KeyRelease)

927811

I want just to know, if I code as follow:-

robot.keyPress(KeyEvent.VK_A);
robot.keyRelease(KeyEvent.VK_A);


Does it guaranteed that the program will simulate key "A", only once?
I mean, when I do not write

<code> robot.keyRelease(KeyEvent.VK_A) </code>

Then the usual output shows :- aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa......... until I press any key, even after program exits.

But when I usually use both statements, this normally not happen. But something strange happens while working last night. I use the following:-

robot.keyPress(KeyEvent.CTRL_MASK) // one more question?- should I use CTRL_DOWN_MASK here, instead
robot.keyPress(KeyEvent.VK_A)

I want to simulate "*ctrl+a*". But instead of expected result (*select all*), I got the following output:-
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa........ (about 16-17 "a", and then it automatically stopped).

Same is the case with "*shift+a*".
The problem happened, when I was running this code in "netbeans environment".

The problem what I'm suspecting is probably due to OS multiprocessing/multithreading environment. Please suggest me to make these two statements atomic, something else to deal with this problem........