Windows installer puts files in system32

Question

Some articles (about tomcat for example) speak about the importance of the java_home variable.
Setting it to the installation root directory enables you to choose which vm use.
Actually windows installer ver. 6 update 4 puts 4 files in system32 directory: java.exe, javaw.exe, javaws.exe, java.cpl.
This means that each installation is not 'self-contained' in his directory (C:\program files\java\jdk...) and there is a 'default' version "system-wide".
Moreover, the installer does not set any java_home variable.
The question is: is this approach based on java_home specific to the integration with tomcat or is it a java standard but it's left to the user?
tnx in adv
Agostino
Edited by: agostino75 on Nov 17, 2008 3:33 AM

Answer 1

Installing a JRE place the files you mentioned in the system32 directory - so, the last installed JRE's files overwrite any copies placed by earlier installs. If you delete these files, then [usually] you can't run java by typing just "java"
Installing the JDK doesn't place files in the system32 directory.
The computer's PATH environment variable [usually] lists the system32 directory before any other directory that contains these files, so they're the ones executed. If you change the PATH so that some other directory [if any] that contains these java files is listed before system32, then the other directory's files will be found first and executed.
In other words, Java doesn't control which are executed, your computer's os does.