'Could not reserve enough space for object heap' when running java -version

Question

I know this is a common question/problem. I'm wondering where to get started with it.

Running java on windows server 2008, we have 65GB memory, and it shows 25GB free. (Currently a couple of guys are running processes).

systeminfo | grep -i memory

shows:

Total Physical Memory: 65, 536 MB
Available Physical Memory: 26,512MB
Virtual Memory: Max Size 69,630 MB
Virtual Memory: Available 299 MB
Virtual Memory: In Use: 69, 331 MB.

Really just wondering how I go about solving this problem.

• Where do I start?
• What does it mean that more virtual memory is being used than physical memory, and is this why java won't start?
• Does java want to use virtual memory rather than physical memory?

java -version

gives me:

Error occured during initialization of VM could not reserve enough space for object heap

More specific questions:

• Why doesn't the JVM want to use the free phsyical memory?
• How much memory does a java command (like java -version ) want to use if you don't specify Xms parameters?
• Would simply assigning more virtual memory be a good solution to the problem?

Answer 1

I got the same issue. From the analysis, we found that the machine have low swap space. Please increase the swap space and verify.

Answer 2

As I discovered when I had a similar problem (though with a lot less memory on the system -- see Cannot run a 64-bit JVM in 64-bit Windows 7 with a large heap size ), on Windows the JVM will try to allocate a contiguous block of memory.

So my bet is that while you have enough total memory, you don't have enough contiguous memory.

Answer 3

At least to see java version run java -Xmx64m -version this should show you the version if needed. Then you can try increasing Xmx and see at what value it fails