How can I tell python to use 64bit java?

Question

In windows command line, if I type java -version, I get

java version "1.7.0_07"
Java(TM) SE Runtime Environment (build 1.7.0_07-b10)
Java HotSpot(TM) 64-Bit Server VM (build 23.3-b01, mixed mode)

and python -v

#snip
Python 2.7.3 (default, Apr 10 2012, 23:31:26) [MSC v.1500 32 bit (Intel)] on win32

In python if use

call("java -version")

I get

java version "1.7.0_25"
Java(TM) SE Runtime Environment (build 1.7.0_25-b17)
Java HotSpot(TM) Client VM (build 23.25-b01, mixed mode, sharing)

Is there a way I can force my python to use the 64bit JVM?

Answer 1

When you call java -version in your windows command line it will consult the PATH environment variable to locate the java executable.

subprocess.call which I assume you are using there seems to not use that same windows PATH variable on Windows in your case. Perhaps if you enforced that it spawns a shell (which is not considered safe according to the docu) it would work.

call("java -version", shell=True)

In case you have multiple Java installations (i.e a 64 bit and 32 bit JRE), the easiest solution would be to hardcode the absolute path to your java 64 bit executable

call("C:\\Program Files\\Java\\jre7\\bin\\java -version")