sudo apt-get install default-jre:i386

Explanation:

In Debian (and Ubuntu, which is based on it), you can install the same package for multiple architectures side by side - this is called "multiarch". When installing a package, the part after the colon indicates the architecture (in this case i386, i.e. 32bit). Without the colon part, you get the default architecture. See the MultiarchHOWTO for details.

Download of Java 32-Bit-Version for Linux: https://www.java.com/en/download/linux_manual.jsp

The OpenJDK is part of Ubuntu's main repository, so it can be installed with the usual Ubuntu tools. You want package openjdk-7-jdk or openjdk-8-jdk.

Thanks to the "MultiArch" feature Ubuntu inherited from Debian, you can install the 32-bit version of a package on a 64-bit system using the usual tools, such as apt-get or aptitude. Just append :i386 to the package name. For example:

sudo apt-get install openjdk-7-jdk:i386

Any required i368 libraries will then be installed automatically.

The easiest solution I have found so far is using a great tool called Oraji which automatically does the configuration for you. Here is the brief excerpt from the install instruction created by the Oraji developer:

1. Download latest official 32-Bit Oracle JDK. File name should be jdk-... -linux-i586.tar.gz from http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html

2. Install Oraji on Ubuntu:

   sudo add-apt-repository -y ppa:neurobin/ppa
   sudo apt-get update
   sudo apt-get install oraji
   

3. Java Installation Instruction:

   Run in terminal:

   sudo oraji '/path/to/the/jdk_or_jre_archive'
   

   or run

   sudo /path/to/oraji /path/to/the/jdk_or_jre_archive
   

   after giving the oraji script execution permission if you didn't install the script.

That's it. Now if you want to populate JAVA_HOME and other environment variables run source /etc/profile or logout and login.

For more info like Uninstall, Changing JDK version, just follow this nice tutorial by Oraji developers https://github.com/neurobin/oraji

Have a great day, guys!

It's super easy to have multiple versions of Java installed. Somewhat harder (read: tedious) is switching between versions at a whim.

tldr

1. apt-get one
2. untar the other
3. export paths depending which one you want

apt-get one version

Decide which version you'll mostly be using. Or decide which one you want to have automatic updates. Or flip a coin, whatever. You don't even have to use apt-get; just manually maintain both packages on your system (see next heading).

The point is: it's easier to use Ubuntu's package manager to maintain exactly one version of a package like java. You're gonna take care of the rest.

untar the other

Download a jdk tarball. Extract it to /opt.

switch between them

I let the package manager handle my primary install. I export some vars for the other one when I need it. I work on the command line a lot, so it's an okay solution for me. I bother with:

export JAVA_HOME=/opt/jdk
export PATH=$JAVA_HOME/bin:$PATH

Also, I symlink jdk/ -> jdk1.6.0_3/ because I'm lazy and don't like reconfiguring my .bashrc and other scripts every incremental jdk upgrade.

Environment variables you might care about:

JAVA_LIBDIR
JNI_LIBDIR
JAVAJNI_LIBDIR
JVM_ROOT
JAVA_HOME
PATH

https://askubuntu.com/questions/819996/howto-install-latest-oracle-java-jdk-32-bit-to-linux-xubuntu-14-04-64-bit-ea

All command line.

"The easiest solution I have found so far is using a great tool called Oraji 
which automatically does the configuration for you. Here is the brief 
excerpt from the install instruction created by the Oraji developer:

Download latest official 32-Bit Oracle JDK. File name should be jdk-... - 
linux-i586.tar.gz from 
http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads- 
2133151.html

Install Oraji on Ubuntu:

sudo add-apt-repository -y ppa:neurobin/ppa
sudo apt-get update
sudo apt-get install oraji
Java Installation Instruction:

Run in terminal:

sudo oraji '/path/to/the/jdk_or_jre_archive'
or run

sudo /path/to/oraji /path/to/the/jdk_or_jre_archive
after giving the oraji script execution permission if you didn't install the 
script.

That's it. Now if you want to populate JAVA_HOME and other environment 
variables run source /etc/profile or logout and login.

For more info like Uninstall, Changing JDK version, just follow this nice 
tutorial by Oraji developers https://github.com/neurobin/oraji

Have a great day, guys!"--Chiggiddi (Ubuntu Ask)

To be able to use the 32-bit JVM, you'll need to have the 32-bit compatibility libraries installed. The second error message means that the 32-bit JVM process is trying to load a 64-bit library; that doesn't work.

On Ubuntu you'd have to install the package ia32-libs, which contains the 32-bit compatibility libraries for 64-bit Ubuntu.

UPDATE: Ubuntu 13.10 introduced multi-arch which replaced ia32-libs with libstdc++6:i386 libgcc1:i386 zlib1g:i386 libncurses5:i386. Source: https://stackoverflow.com/a/10473415/14731

I'll try to answer all your questions, but please break them into separate Q&As in the future. It makes it easier for one person to answer.

1. You seem to have a bit of a misunderstanding in regards to 32-bit. x86 is actually 32-bit. x86 is named after a line of old Intel CPUs (I think), but they didn't really have anything to name 64-bit after, so it became x64.

   • Get the x86 version

2. You'll have to adapt the file names a bit, since Java versions have changed, but this Ask Ubuntu Q&A has very extensive installation instructions: How can I install Sun/Oracle's proprietary Java JDK 6/7/8 or JRE?.

3. As for default Java version, you need to have the one you want as default installed, and then you need to select it as the default. How to set default Java version?.

   • The command you want, since it looks like you're dealing with javac, is:

     sudo update-alternatives --config javac
     

   • Replacing javac with java will allow you to change defaults there too.

Honestly, I'm having a hard time understanding your question fully, and I see you don't speak English natively. Hopefully, what I have below will make the whole thing easier.

There's an alternative to Oracle's JDK, called OpenJDK. It's a very simple installation, and I believe it sets itself as the default Java version. To install:

sudo apt-get install openjdk-8-jdk