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Multiple jvm on one linux box

For some reason, you need to use more than one version of jdk on same linux machine. First thing to do is install jdk, you can download from sun. Follow their installation instruction then you should have jdk install in /usr/java/jdk1.6.0_01. but jre still gcj
[root@mail ~]# java -version
java version "1.4.2"
gij (GNU libgcj) version 4.0.2 20051125 (Red Hat 4.0.2-8)

Copyright (C) 2005 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
[root@mail ~]#

So use alternatives command to check
[root@mail ~]# alternatives --display java
java - status is auto.
 link currently points to /usr/lib/jvm/jre-1.4.2-gcj/bin/java
/usr/lib/jvm/jre-1.4.2-gcj/bin/java - priority 1420
 slave rmiregistry: /usr/lib/jvm/jre-1.4.2-gcj/bin/rmiregistry
 slave jre_exports: /usr/lib/jvm-exports/jre-1.4.2-gcj
 slave jre: /usr/lib/jvm/jre-1.4.2-gcj
Current `best' version is /usr/lib/jvm/jre-1.4.2-gcj/bin/java.
[root@mail ~]#

add 'sun java' to alternative,config,and check again
[root@mail ~]# alternatives --install /usr/bin/java java /usr/java/jdk1.6.0_01/bin/java 2 
[root@mail ~]# alternatives --config java 
There are 2 programs which provide 'java'.

  Selection    Command
-----------------------------------------------
*+ 1           /usr/lib/jvm/jre-1.4.2-gcj/bin/java
   2           /usr/java/jdk1.6.0_01/bin/java

Enter to keep the current selection[+], or type selection number: 2
[root@mail ~]# java -version
java version "1.6.0_01"
Java(TM) SE Runtime Environment (build 1.6.0_01-b06)
Java HotSpot(TM) Client VM (build 1.6.0_01-b06, mixed mode, sharing)
[root@mail ~]#


Note: For my ubuntu box I get java from backport extra repos by add this two line in /etc/apt/sources.list
deb http://archive.ubuntu.com/ubuntu dapper-backports main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu dapper-backports main restricted universe multiverse

then use these command to install and config
pnix@pnix-a7:~$sudo apt-get install sun-java6-jdk sun-java6-plugin
pnix@pnix-a7:~$sudo update-alternatives --config java
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Comments

Anonymous said…
Great post and screen shots! Saved the day, ty
February 24, 2011 at 10:39 PM
Anonymous said…
Thanks.

Hasan Ali Özaslan
June 13, 2013 at 7:50 PM
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