Java-Gaming.org Hi !
Featured games (83)
games approved by the League of Dukes
Games in Showcase (540)
Games in Android Showcase (133)
games submitted by our members
Games in WIP (603)
games currently in development
News: Read the Java Gaming Resources, or peek at the official Java tutorials
 
    Home     Help   Search   Login   Register   
Pages: [1]
  ignore  |  Print  
  Java Runtime Process Memory Leak?  (Read 1060 times)
0 Members and 1 Guest are viewing this topic.
Offline concerto49

Junior Devvie





« Posted 2012-11-18 10:23:54 »

This might be a while back, but I was using Java to call external process (e.g. Bash scripts / Windows Dos Scripts) and over time there were memory leaks that eventually would cause crashes. Read about it in forums do.

Does anyone know if this has been fixed in the latest version of Java and/or if it still occurs and ways to get around it?

Thanks.

High performance, fast network, affordable price VPS - Cloud Shards
Available in Texas, New York & Los Angeles
Need a VPS Upgrade?
Offline Alan_W

JGO Knight


Medals: 8
Projects: 3


Java tames rock!


« Reply #1 - Posted 2012-11-18 19:46:12 »

The leak is usually due to the called process not freeing resources before being terminated.

See the last comment at https://forums.oracle.com/forums/thread.jspa?threadID=2185235

Similar problems occur when calling C code through JNI.  It is easy to forget you have to do your own cleanup and dispose of any allocated buffers.

Time flies like a bird. Fruit flies like a banana.
Offline sproingie

JGO Kernel


Medals: 202



« Reply #2 - Posted 2012-11-19 16:20:43 »

If you spawn external processes, you need to make sure to use Process.waitFor() to ensure the process properly exits and closes stdin/stdout/stderr.  If you don't, the process may stick around and not only keep consuming overall system memory, it'll also keep the file descriptor open til you run out.
Games published by our own members! Check 'em out!
Legends of Yore - The Casual Retro Roguelike
Offline Riven
« League of Dukes »

« JGO Overlord »


Medals: 847
Projects: 4
Exp: 16 years


Hand over your head.


« Reply #3 - Posted 2012-11-19 16:22:59 »

At the same time, not reading stdout/stderr may block the process, which means waitFor() never returns.

So, read stdout/stderr from two other threads, and block on waitFor() on the current thread.

Hi, appreciate more people! Σ ♥ = ¾
Learn how to award medals... and work your way up the social
Offline Alan_W

JGO Knight


Medals: 8
Projects: 3


Java tames rock!


« Reply #4 - Posted 2012-11-19 20:09:27 »

Can you do it all on the current thread by something like the following pseudo code?

while !eof(stdin) || !eof(stderr) {
if !eof(stdin) read(stdin)
if !eof(stderr) read(stderr)
}
close(stdin)
close(stderr)
wait_for_process_termination_and_get_exit_code()

I suppose there's a risk that the process could generate some more output after we've exited the while loop, which would cause the waitFor to block.

If we put the code to empty stdin and stderr on another thread, I assume that it must loop until after the main thread successfully gets the exit code, at which point the main thread must signal it to exit (needs a semaphore).  That does mean that stdin and stderr can't be explicitly closed, prior to the waitFor.  Does the waitFor close the streams automatically?

Time flies like a bird. Fruit flies like a banana.
Pages: [1]
  ignore  |  Print  
 
 
You cannot reply to this message, because it is very, very old.

 

Add your game by posting it in the WIP section,
or publish it in Showcase.

The first screenshot will be displayed as a thumbnail.

Mr.CodeIt (24 views)
2014-12-23 03:34:11

rwatson462 (53 views)
2014-12-15 09:26:44

Mr.CodeIt (45 views)
2014-12-14 19:50:38

BurntPizza (85 views)
2014-12-09 22:41:13

BurntPizza (110 views)
2014-12-08 04:46:31

JscottyBieshaar (79 views)
2014-12-05 12:39:02

SHC (89 views)
2014-12-03 16:27:13

CopyableCougar4 (96 views)
2014-11-29 21:32:03

toopeicgaming1999 (155 views)
2014-11-26 15:22:04

toopeicgaming1999 (152 views)
2014-11-26 15:20:36
Resources for WIP games
by kpars
2014-12-18 10:26:14

Understanding relations between setOrigin, setScale and setPosition in libGdx
by mbabuskov
2014-10-09 22:35:00

Definite guide to supporting multiple device resolutions on Android (2014)
by mbabuskov
2014-10-02 22:36:02

List of Learning Resources
by Longor1996
2014-08-16 10:40:00

List of Learning Resources
by SilverTiger
2014-08-05 19:33:27

Resources for WIP games
by CogWheelz
2014-08-01 16:20:17

Resources for WIP games
by CogWheelz
2014-08-01 16:19:50

List of Learning Resources
by SilverTiger
2014-07-31 16:29:50
java-gaming.org is not responsible for the content posted by its members, including references to external websites, and other references that may or may not have a relation with our primarily gaming and game production oriented community. inquiries and complaints can be sent via email to the info‑account of the company managing the website of java‑gaming.org
Powered by MySQL Powered by PHP Powered by SMF 1.1.18 | SMF © 2013, Simple Machines | Managed by Enhanced Four Valid XHTML 1.0! Valid CSS!