- java -version => check to see if the default is a “server” VM or a “client” VM. On my mac (the default is a server VM):
$ java -version
java version “1.6.0_26″
Java(TM) SE Runtime Environment (build 1.6.0_26-b03-384-10M3425)
Java HotSpot(TM) 64-Bit Server VM (build 20.1-b02-384, mixed mode)
- Make sure that you are running 32 bit or 64 bit VM by running the following command:
$ file /usr/bin/java
/usr/bin/java: Mach-O universal binary with 3 architectures
/usr/bin/java (for architecture x86_64): Mach-O 64-bit executable x86_64
/usr/bin/java (for architecture i386): Mach-O executable i386
/usr/bin/java (for architecture ppc7400): Mach-O executable ppc
- On Solaris, you would need to install 64 bit support explicitly (as of Solaris-Sparc 10). All you need to do is to download the 64 bit self installing sh file and run it in the same folder as the existing 32 bit installation.
- To test the Virtual Memory that your process utilized run the following command:
ps -eafl -o vsz,rss => here vsz: is the total memory including in RAM and rss: is the total memory in RAM.
- To confirm the bitness (32 vs 64) of a running JVM process, use jinfo:
jinfo -d64 -sysprops [pid]
And look for “sun.arch.data.model = 64″ property.
- To view the swap available, you need to either use top, vmstat (on solaris, check the swap column => that specifies the swap available)
- On solaris, use prstat to figure out the no of threads that a process is spawning.