How to determine 32-bit OS or 64-bit OS from Java application

Question

I know how to check whether the JVM is 32 or 64-bit is running on a current Machine using java program. But is there any possibility to know if the OS on current machine is 32-bit or 64-bit.

Please let me know how to determine using Java Program.

Answer 1

System.getProperty("os.arch");

Should be available on all platforms, see the Java System Properties Tutorial for more information.

But 64 bit Windows platforms will lie to the JVM if it is a 32 bit JVM. Actually 64 bit Windows will lie to any 32 bit process about the environment to help old 32 bit programs work properly on a 64 bit OS. Read the MSDN article about WOW64 for more information.

As a result of WOW64, a 32 bit JVM calling System.getProperty("os.arch") will return "x86". If you want to get the real architecture of the underlying OS on Windows, use the following logic:

String arch = System.getenv("PROCESSOR_ARCHITECTURE");
String wow64Arch = System.getenv("PROCESSOR_ARCHITEW6432");

String realArch = arch != null && arch.endsWith("64")
                  || wow64Arch != null && wow64Arch.endsWith("64")
                      ? "64" : "32";

This question was answered by ChrisH.

Answer 2

You can run

System.getProperty("os.arch")

to retrieve the systems architecture. My Windows 64bit system will return amd64 as os.arch value.