java.exe

Hi I have multiple installations of jre on my machine, how can I check which jre is reffered when I am using "java" command. I can check the version but I want to know exactly which java.exe is getting executed. please let me know if there is any env variable which stores it.

hi, my problem is when i installed java 1.2 or 1.4 and whan i tried to compile in dos mode, it gives me error message java.exe or javac.exe has encountered problem .when i clicked details it gives message KERNEL32 has problem. what should i do? i even tried to install diffrent versions of java...