After installation of 32-bit or 64-bit jdk at 64-bit windows (windows xp and windows 2003 SE tried) on amd64 system calling 

java -version

does not give you a result - it says 

'java' is not recognized as an internal or external command, operable program or batch file.

This is unlike the behaviour after jdk installation on other platforms which breaks similarity of usage of "java -version" during tests. I guess the reason is that we use 32-bit registry access API to store information about jdk installed. On 64-bit windows it gets placed to some compatibility area (Wow6432Node). After we call "java -version" this information is not found. So I suggest that we either look at two places in the registry or use 64-bit API to store the information.