Install JDK in D:\Apps\1.3.1, but classpath=C:\Program Files\JavaSoft\JRE\

Question

I installed the 1.3.1_01 JDK at D:\Apps\1.3.1, but a second copy of the hotspot jvm is installed at C:\Program Files\JavaSoft\JRE\1.3.1\bin. I can find no way to prevent the JDK install program from doing this (w2K sp2).
I wouldn't care, but many programs keep using the C: version. My PATH variable only points to the D: directory, but if I open a cmd window and type java it runs the C: copy. When I installed JEdit 3.2.2 it starts up saying java.home is C:\Program... and I should add tools.jar to my classpath. Well, tools.jar is in my CLASSPATH. It points to the tools.jar on my D: drive!
Does anyone know what is going on? How can I get all programs to point to the java.exe version that is specified in my environment variables?
Thank you in advance,
Kevin

Answer 1

Under Windows, some programs assume that Java is started by %Windows_Dir%\System32\Java.exe. This version will look in the registry to get the current version of Java. The key it checks:
HKEY_LOCAL_MACHINE\Software\Javasoft\Java Runtime Environment\CurrentVersion
In my case, this key says 1.4, so it goes into the 1.4 registry key and finds this:
JavaHome=C:\Program Files\JavaSoft\JRE\1.4
So that's where it generally comes from.
If you explicitly run the java.exe from a specific Java install directory, it will use that directory as the home though.