Mock Exam No.1 Marcus Green

[Chris Lenz]

Hi *,
Question 19:
http://www.jchq.net/mockexams/exam1.htm
----
When I compile and run the code, it prints
just "vandeleur" and nothing else...
Will say, the run() will never be called.
I tested with JBuilder 5.0
cu
Chris

[John Lee]

I run the program from command line, getting the same result as you. My jdk version is jdk1.3.1_01.

[Marcus Green]

The fact that it prints only "vandeleur" on your computer, my computer, computer and several others does not mean you can be certain that is what will always be output.
Threading is non-deterministic.
You cannot be certain where the thread execution has got to by the time the output is called. This is a very important issue with threading and not at all obvious.
[ February 25, 2003: Message edited by: Marcus Green ]

[Chris Lenz]

Hi Marcus,
in this case, perhaps it would be better to offer another possibility to answer?
Perhaps that�s possible that there is an ouput of only "vandeleur" ?
By the way, a very, very good Mock Exam!
by
Chris

[John Lee]

Hi Marcus:
Thanks for the explaination. I did an experiment, adding a print statement in run(). The result shows run() get excuted, but after the print statement in main().
So it looks like run() thread get excuted slower, at least in my case.
Thanks again for the good mock exam.
Best Regards,
Don Liu

[Dan Chisholm]

This does not appear to be errata so I will move it to the Java Programmer Certification forum.

[Marcus Green]

Good move Dan. This is a stinker of a topic and it it is worth taking a look at this question to get the gist of the issue. The people who set the questions love to hammer your understanding of threading.
Marcus