Could not reserve enough space for object heap to start JVM

Question

Just faced with strange issue. When i type

java -version

i got

Error occurred during initialization of VM
Could not reserve         


        

Answer 1

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?