Installing different Java JRE on Linux » @cyberfellabtc, since 2012.

It you need to install a newer/alternative/multiple version(s) of the Java Runtime Environment on a RHEL Server, read the following guide. It will enable you to switch between multiple installed JRE’s. This can be useful for development / pre-prod servers, where prod is running a different version.

If you have a requirement to run multiple JREs on a single RHEL server, then use the “alternatives” package to facilitate switching between them via a convenient menu system. Notes on configuring alternatives are at the end of this post.

CHECK PROD JRE VER
[matt@CyberfellaProdSvr ~]$ java -version
java version “1.7.0_67”
Java(TM) SE Runtime Environment (build 1.7.0_67-b01)
Java HotSpot(TM) 64-Bit Server VM (build 24.65-b04, mixed mode)

CHECK PRE-PROD JRE VER
[matt@CyberfellaPreSvr JRE 1.7.65]$ java -version
java version “1.6.0_34”
OpenJDK Runtime Environment (IcedTea6 1.13.6) (rhel-1.13.6.1.el6_6-x86_64)
OpenJDK 64-Bit Server VM (build 23.25-b01, mixed mode)

CHECK EXISTING JRE(s) INSTALLED
rpm -qa | sort | grep ^j
java-1.5.0-gcj-1.5.0.0-29.1.el6.x86_64
java-1.6.0-openjdk-1.6.0.34-1.13.6.1.el6_6.x86_64
java-1.6.0-openjdk-devel-1.6.0.34-1.13.6.1.el6_6.x86_64

DOWNLOAD JRE VERSION
The latest version of JRE (Java Runtime Environment) is easy to find. The older ones, not so much. You’ll need an Oracle Support Account. Don’t panic, it’s free to set up.

WINSCP JRE TO LINUX SERVER
Install WinSCP on Windows. It will prompt to import all your PuTTY Sessions! How Convenient! I love stuff that saves time.
Using WinSCP on Windows, SCP JRE 1.7.67 to the server.

INSTALL/UPGRADE JRE 1.7.67
rpm -Uvh jre-7u67-linux-x64.rpm

ADDING JAVA to ALTERNATIVES
View current selection of different JREs in alternatives
alternatives –config java
Add new version after installing rpm
alternatives –install <exe path> <binary> <install path> <selection>
alternatives –install /usr/bin/java java /usr/java/jre1.7.0_67/bin/java 3
Switch to new version
update-alternatives –config java
or just “alternatives –config java” seems to do the same thing.
Show current JRE
java -version