Download and install the Java Developement Kit (JDK):
http://java.sun.com/javase/downloads/index.html
DDJ can work with different databases.
The default database is ACCESS.
Therefore, with the standard version, it is needed to have installed the ODBC driver for Access 2007.
This is automatically installed when installing Access 2007 or any other higher version.
(Optional) Download SWT.
DDJ already has a version of SWT. But the last version can be also used. The last version can be downloaded from:
http://www.eclipse.org/swt
Prepare the Java project
Install JDK (for instance in c:\program files\java\).
(Optional) Unzip SWT into a folder (the name of the folder is something like swt-3.3.2-win32-win32-x86).
Do not install it, just unzip.
Unzip DDJ in the hard disk.
Open Eclipse and import the DDJ project (Import the 2 folders previosly unzipped).
Import JDK
Right button in the DDJ project (inside Eclipse, in the Project Explorer view).