CODEWITHSUNDEEP
javaexceptionjvmheap-memory
bigbass1997
bigbass1997

Reputation: 175

Why I am getting a JVM max heap space error?

I am trying to run a certain java program with more than 1024M heap space. Even though I have 4GB of RAM and a 32bit OS, its saying that the max is 1024M. Below is the batch code I am trying to use to start the program:

@echo off
java -Xmx2048M -Xms2048M -jar program.jar

Could someone explain why I am getting a JVM "could not reserve enough space" error?

Upvotes: 0

Views: 851

Answers (2)

pyrometer
pyrometer

Reputation: 881

You are getting the "could not reserve enough space" error because there must be no contiguous block of memory available in your RAM of size 2048M. I would suggest that you either reduce the -Xms to 512M since I don't think initially you will require 2048M heap space. If this doesnt work, then you will need to reduce the -Xmx value.

Upvotes: 0

nos
nos

Reputation: 229342

You're on Windows, and the max address space a single 32 bit program can have is 2GB. Now since the process and system needs some of that for housekeeping stuff (e.g. .dlls) , you can't use all those 2GB for the java heap. So try with less, e.g. 1.5 GB.

You can make 32 bit programs get 3GB of address space through a boot switch, see here , which can be an alternative to switching to a 64 bit OS if you really need more heap space.

Upvotes: 1

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