Installing java on your linux machine without removing the native version it comes with

I like to have all my software installations in a single place so I know exactly what state my machine is in by glancing at a single directory, say ~/Software
My ancient CentOs setup doesn't have jdk 1.7 in its repo, so instead of fooling around with alternatives <shudder>, I downloaded the jdk version I wanted and put it into said ~/Software directory.

Here's a simple way to go about changing the default version of java that your system picks up without having to uninstall the native java that it comes with.

1. Switch to su
2. Create a file,say java.sh in /etc/profile.d/ containing :

#!/bin/bash
         
JAVA_HOME=/home/ShankarV/Software/jdk1.7.0_40/
                     
PATH=$PATH:$JAVA_HOME/bin:
                                     
export PATH JAVA_HOME

3. Save out the file, and logout and log back in to your machine.
4. To test out your java version, run
java -version
5. To see which executable will be picked up, run
which java

Installing 32 bit java on my 64 bit CentOs6 machine

This is a right old pain to do, so unless you really need to, I would say find a way to stick to the native 64 bit jre/jdk install.
As of this writing, the latest jdk version available is 1.7.0_40

A quick listing of the steps I followed are below. The commands are italicised.

1. yum erase jdk (to remove the existing 64 bit java devel environment)

2. Download the x86 version of jdk (the rpm), say jdk-7u40-linux-i586.rpm

3. yum provides  libgcc_s.so.1
    yum install libgcc-4.4.7-3.el6.i686 
(which is what came up as the reqd package from the command above)

4. yum install jdk-7u40-linux-i586.rpm

5. Check your installation with the usual 
    java -version

In case you want both the 64 and 32 bit versions of java installed, you'll have to muck about with alternatives, which I happily chose to avoid!