Installing Eclipse IDE on Debian Linux
Eclipse is an open source user interface platform. It provides IDEs (Integrated Development Environments) for several programming languages, including Java and Scala.
Eclipse website is here: www.eclipse.org

This document explains how to install Eclipse IDE for Java programming language.
This document assumes you have root access to your Linux box. If not you should install Eclipse somewhere in your home directory.
If you have root access you can install Eclipse into a shared directory, and every user will have his/her own configuration saved in home directory.
If you do not have root access, or do not want to share Eclipse installation, scroll down to Single user installation .

Download Eclipse
Open this link in your browser: www.eclipse.org/downloads
Find Eclipse IDE for Java Developers and select 32 or 64 bit version.
To find out if you have 32 or 64 bit operating system open a terminal window.

On Gnome desktop you can open a terminal from Applications menu ( Applications/Accessories/Terminal ).
Press ENTER after each command.

uname -m
// i686 means you have 32 bit Linux
// x86_64 means you have 64 bit Linux

Click on appropriate link ( Linux 32 bit or Linux 64 bit ), then click on green arrow.
Download should start, save that file (e.g. eclipse-java-kepler-SR1-linux-gtk-x86_64.tar.gz ) to disk (e.g. to Downloads directory).

If you have root access:

cd /opt
mkdir eclipse
cd eclipse
mv /home/{user}/Downloads/eclipse-java-kepler-SR1-linux-gtk-x86_64.tar.gz .
tar xvf eclipse-java-kepler-SR1-linux-gtk-x86_64.tar.gz
rm eclipse-java-kepler-SR1-linux-gtk-x86_64.tar.gz
mv eclipse kepler-sr1
ln -s kepler-sr1 default

At this point you should see /opt/eclipse/default directory (owned by root user).

Having a default link will help with upgrading Eclipse version later on. Once you download a new version you can remove that link and create a new one with the same name but pointed to new directory.

Create Eclipse link in /etc/alternatives

cd /etc/alternatives
ln -s /opt/eclipse/default/eclipse

Note
Command ln usually takes 2 parameters (source file name and target file name) but if target file name is the same as source file name you can skip the second parameter.

Create Eclipse link in /usr/local/bin

cd /usr/local/bin
ln -s /etc/alternatives/eclipse

At this point typing:

which eclipse

Should print:

/usr/local/bin/eclipse

If that does not work check if /usr/local/bin is part of default path:

set | grep PATH

On my system that prints:

PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin

If you do not see /usr/local/bin edit your /etc/profile file:

cd /etc
vi profile
// add this line at the end:
export PATH=/usr/local/bin:$PATH

User specific Eclipse configuration is located in home folder, for example:

/home/{user}/.eclipse/org.eclipse.platform_4.3.0_1449841019_linux_gtk_x86_64

Single user installation

cd /home/{user}
mkdir eclipse
cd eclipse
mv /home/{user}/Downloads/eclipse-java-kepler-SR1-linux-gtk-x86_64.tar.gz .
tar xvf eclipse-java-kepler-SR1-linux-gtk-x86_64.tar.gz
rm eclipse-java-kepler-SR1-linux-gtk-x86_64.tar.gz
mv eclipse kepler-sr1
ln -s kepler-sr1 default

At this point you should see /home/{user}/eclipse/default directory (owned by your regular user).

Test Eclipse IDE
Log in as regular user, type eclipse on command line and press enter.
If you performed single user installation make sure you are in /home/{user}/eclipse/default directory.

Eclipse IDE should show up and ask you to choose your workspace directory. I usually choose /home/{user}/workspace folder but you can choose any folder you have read/write access to.
Exit Eclipse.

Update Eclipse memory settings
Default memory settings for Eclipse are usually a bit low so it is good to adjust those.
If you installed Eclipse as root user you will need to log in as root again and go to /opt/eclipse/default folder.
Otherwise go to /home/{user}/eclipse/default folder.

Open eclipse.ini in a text editor and make the following changes:

-XX:MaxPermSize=256m
-XX:PermSize=512m
-Xms512m
-Xmx1024m
-XX:+UseParallelGC

Save and close text editor.
For some plugins (e.g. Scala IDE plugin) heap size of 1024 MB could be low. I usually set Xmx value to 2048m.
Check how much memory your box has and set this value accordingly. You can check available memory with free command.

At this point you should be good to go. See below for some additional tips on customizing Eclipse IDE.

Create Eclipse Gnome desktop launcher
Right click on empty desktop area, select Create launcher... option.
Left click on icon image, navigate to File System/opt/eclipse/default and select icon.xpm file.
Enter Eclipse Kepler under Name (or anything you want).
If you installed Eclipse as root enter /opt/eclipse/default/eclipse under Command .
If you installed Eclipse as a regular user enter /home/{user}/eclipse/default/eclipse under Command .
Click OK .

To disable folding: Start Eclipse, go to Window/Preferences/Java/Editor/Folding, uncheck Enable folding box.