How do we determine the JRE version (32 bit or 64 bit)

$ java -version

java version "1.5.0_01"

Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_01-b08)

Java HotSpot(TM) Server VM (build 1.5.0_01-b08, mixed mode)

versus

$ java -d64 -version

java version "1.5.0_01"

Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_01-b08)

Java HotSpot(TM) 64-Bit Server VM (build 1.5.0_01-b08, mixed mode)

If you don't have the 64 bit overlay installed, you will get something like:

$ java -d64 -version

execve(): No such file or directory

Error trying to exec jdk1.5.0_02/bin/sparcv9/java.

Check if file exists and permissions are set correctly.

Failed to start a 64-bit JVM process from a 32-bit JVM.

Verify all necessary J2SE components have been installed.

(Solaris SPARC 64-bit components must be installed after 32-bit components.)

Running in 32bit mode, you're limited to 4gb minus overhead ... so usually somewhere over 3gb of java heap size..

Running in 64bit mode, I don't think you can reach a limit easy... Physical memory will be the limit.

hydr0gen1a at 2007-7-10 3:48:15 >