increase the java heap size permanently?

Question

Is there a way that I can set the default heap size for the jvm on my own computer? I want to set it to 1g, because I'm always running custom programs that always hit the overage point in the default jvm size.

I just dont want to have to remember to type -XmX1g everytime I run my java app from the command line...

There has to be an admin way to do this right?

Note, the latest Java 6 releases from Sun have increased standard heap limits. — Thorbjørn Ravn Andersen, Jan 15 '10 at 18:53

Kutzi · Answer 1 · 2015-12-02T16:16:41.213

66

Apparently, _JAVA_OPTIONS works on Linux, too:

$ export _JAVA_OPTIONS="-Xmx1g"
$ java -jar jconsole.jar &
Picked up _JAVA_OPTIONS: -Xmx1g

edited Dec 02 '15 at 16:16

answered Oct 02 '09 at 10:00

Kutzi

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I'd suggest replacing the ">" with "$" as the linux terminal prompt ends with $. At first I got confused by your answer as it resembles similar structure to a sub cli within the terminal. (eg. mysql)... which evidently has a prompt of '>'. Thanks for your answer (which, in my opinion should be the approved answer)... fingers crossed that my long running script doesn't fail after 3 hours now, changed my java heap size from 500mb to 2gb! Also, I was unsure if the 3rd line 'Picked...' was a part of the 2nd line.. so I tried both. (if that's just an output... would suggest prefix of 'Output: '. :) – josh.thomson Apr 28 '15 at 08:04
Thanks @josh.thomson, I've updated the answer with your suggestion – Kutzi Dec 02 '15 at 16:17

score 25 · Answer 2 · edited Jun 01 '17 at 13:57

25

This worked for me:

export _JAVA_OPTIONS="-Xmx1g"

It's important that you have no spaces because for me it did not work. I would suggest just copying and pasting. Then I ran:

java -XshowSettings:vm

and it will tell you:

Picked up _JAVA_OPTIONS: -Xmx1g

edited Jun 01 '17 at 13:57

DIF

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answered Jun 01 '17 at 13:00

Justin Chitla

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It worked for me but after some time it is going down to same heap size as it was before on my ec2 tomcat – Onkar Musale Aug 06 '19 at 13:09

score 24 · Answer 3 · answered May 19 '09 at 03:50

24

For Windows users, you can add a system environment variable named _JAVA_OPTIONS, and set the heap size values there. The JVM should be able to grab the virtual machine options from _JAVA_OPTIONS.

answered May 19 '09 at 03:50

The Dissonant

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The windows solution can be reached [here](http://stackoverflow.com/a/17369724/1635051). – Reza Ameri Jun 29 '13 at 05:39

score 4 · Answer 4 · edited Nov 12 '19 at 20:22

4

what platform are you running?..
if its unix, maybe adding

alias java='java -Xmx1g'

to .bashrc (or similar) work

edit: Changing XmX to Xmx

edited Nov 12 '19 at 20:22

Nam Vu

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answered May 19 '09 at 03:48

Aditya Mukherji

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score 2 · Answer 5 · edited Feb 01 '22 at 13:18

2

if the platform is Linux, then adding an entry in bash_profile will help.

vim ~/.bash_profile

then add

export _JAVA_OPTIONS="-Xmx4g"

edited Feb 01 '22 at 13:18

Syscall

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answered Feb 01 '22 at 12:58

mauryaAjay

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increase the java heap size permanently?

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