Problem with Simultaneous JRockit Installations on Windows

Question

Hi,
I have two instances of JRockit installed on Windows XP - 1.4.2_08-b03 and 1.5.0_04-b05.
I require this configuration to support two projects which use these versions independently of each other.
Having installed 1.4 and then 1.5 (in that order), execution of "java -version" from an arbitrary directory yields 1.5 as the operative installation.
There is no reference to either installation in the PATH environment variable.
Adding the 1.4 bin to the PATH, has no effect - "java -version" still returns 1.5 as the operative version.
What has the Windows distribution of JRockit 1.5 done as an alternative to modifying the PATH environment variable? What can I do in order to "select" the appropriate version at the appropriate time?
The only way that I can get "java -version" to reply with 1.4 as the operative version is if I type this command under the 1.4 bin directory.
Very frustrated - any help would be greatly appreciated?
Matt Hansen

Answer 1

Matt,
when installing the JRockit JRE on Windows, the launcher files java.exe and
javaw.exe (and in some earlier versions that support Java Plugin and Java
Web Start also javaws.exe and jpicpl32.cpl) are automatically copied to the
system directory, e.g. c:\winnt\system32 (see GetSystemDirectory Windows
API).
This is identical behaviour to the Sun JRE installer.
The system invariant is that if there are multiple JREs installed on the
machine then the JRE with the highest version number will be integrated with
the system, i.e. having java.exe and javaw.exe in the system directory, be
associated to automatically launch .jar files, etc.
In your case 1.5.0_04 is higher than 1.4.2_08 and no matter what
installation order, the java.exe and javaw.exe from 1.5.0_04 will exist in
the system directory.
It is always possible to update %PATH% by ensuring that the <jrehome>/bin
directory of the preferred JRE appears before the windows system directory
in %PATH%.
But since you need to support two different projects it wold be simpler for
you to have two CMD/BAT files, e.g. go_jre_14.cmd and go_jre_15.cmd that
updates the PATH variable before you start working on either of the two
different projects. Also, most IDE tools like e.g. Eclipse, allows you to
explicitly define what JDK/JRE you need to work with for each different
project.
Best Regards
/Robert
<Matthew Hansen> wrote in message news:[email protected]...
Hi,
I have two instances of JRockit installed on Windows XP - 1.4.2_08-b03 and1.5.0_04-b05.
>
I require this configuration to support two projects which use theseversions independently of each other.
>
Having installed 1.4 and then 1.5 (in that order), execution of"java -version" from an arbitrary directory yields 1.5 as the operative
installation.
>
There is no reference to either installation in the PATH environmentvariable.
>
Adding the 1.4 bin to the PATH, has no effect - "java -version" stillreturns 1.5 as the operative version.
>
What has the Windows distribution of JRockit 1.5 done as an alternative tomodifying the PATH environment variable? What can I do in order to
"select" the appropriate version at the appropriate time?
>
The only way that I can get "java -version" to reply with 1.4 as theoperative version is if I type this command under the 1.4 bin directory.
>
Very frustrated - any help would be greatly appreciated?
Matt Hansen