Eclipse is an Interactive Development Environment for many languages, especially Java and C++/C. It includes web development tools, data modeling tools, and many other features. Because it integrates access to version control (CVS and Subversion), it makes collaboration with other programmers easy.

Installing Eclipse

Here are instructions for setting up a 64-bit Eclipse 3.6 (Helios) on Snow Leopard, tested August 2010.

These instructions also work to install Eclipse 3.7 (Indigo) on OSX Lion (10.7), tested February 2012.

1. Make a copy of your workspace if you are upgrading from an older version.
2. Navigate your browser to www.eclipse.org/downloads
3. Download the "Eclipse IDE for Java Developers" 64-bit Mac package, untar it, and install in /Applications.
4. Start Eclipse. When it asks for a workspace, specify your new copy.

Subversion

I use Subversion for version control on several projects. Our repository is on a Unix system.

1. In Help ► Eclipse Marketplace... search for Subclipse, and click to add it. Accept the license, click Finish, and restart Eclipse.
2. Your workspace will appear.
3. Go to  collab.net, select the correct OSX package for your OS, try to download. (The first time you do this, it will tell you to register and surrender your name and mail address. Fill out the form and click Register. Wait. An email will arive in less than an hour with a link to a web page where you can set your password. Do so.) Return to your attempt to download, log in, and the file will download. Double click the JavaHL file and it will mount. Double click to run the installer and install.
4. Restart Eclipse again. You should not need to give any passwords or reload any files, if you had subclipse running on a previous version.
5. (If any project used to be a Java project and now is not, delete it, keeping the files, and add it with the same name, specifying a Java project.)