Could not reserve enough space for object heap to start JVM

Just faced with strange issue. When i type

java -version

i got

Error occurred during initialization of VM
Could not reserve enough space for object heap
Could not create the Java virtual machine.

.

java -Xms64m -Xmx64m -version

This command works fine

java version "1.6.0_24"
Java(TM) SE Runtime Environment (build 1.6.0_24-b07)
Java HotSpot(TM) Client VM (build 19.1-b02, mixed mode)

If i change xms, xmx to 128m, i get error again.

Using top command and free -开发者_高级运维m i can see, that i got over 192 mb free, so why i still get this error ?

Mem:    262144k total,    64760k used,   197384k free,        0k buffers
Swap:        0k total,        0k used,        0k free,        0k cached

Thank you

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I had the same problem when using a 32 bit version of java in a 64 bit environment. When using 64 java in a 64 OS it was ok.

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It looks like the machine you're trying to run this on has only 256 MB memory.

Maybe the JVM tries to allocate a large, contiguous block of 64 MB memory. The 192 MB that you have free might be fragmented into smaller pieces, so that there is no contiguous block of 64 MB free to allocate.

Try starting your Java program with a smaller heap size, for example:

java -Xms16m ...

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According to this post this error message means:

Heap size is larger than your computer's physical memory.

Edit: Heap is not the only memory that is reserved, I suppose. At least there are other JVM settings like PermGenSpace that ask for the memory. With heap size 128M and a PermGenSpace of 64M you already fill the space available.

Why not downsize other memory settings to free up space for the heap?