Update Guide: How to update JBoss Developer Studio 2.0 To 2.1
This guide will provide you with detailed info on how to update from an existing JBDS 2.0 installation to JBDS 2.1.
Installation From Update Site
If you plan to use JBDS 2.1 with JBoss EAP 5, you will need to first install Sun JDK 6.
Fedora/RHEL users can also use 'yum install java-1.6.0-openjdk-devel' to install OpenJDK 6. Note that gcj/gij is NOT supported.
Start JBDS, then go to Help > Software Updates... > Available Software > Manage Sites... > Add...
Paste in the following URL: https://devstudio.jboss.com/updates/2.1/
Note: On some platforms, you may also be able to drag and drop the link from your browser directly into Eclipse.

Enter your username and password. You may be prompted twice. If you do not know your username and password, download the Release Notes from CSP or contact Red Hat Customer Support.

Select features to update or install, then click Install...

Install. Restart when prompted.

If the install gets stuck on a particular jar download (bandwidth saturation, slow mirror, etc.), you can shut down JBDS and try again.
Ignore any errors you get when starting the second time - a completed install should resolve them so that when you restart the third time you will be ready to go.