So, you want to build VE locally, so that you can contribute to the project? Awesome. Here's what you'll need:
For VE 1.4, you'll need Eclipse 3.4.2 SDK and related requirements. For VE 1.5, you'll need Eclipse 3.5.x SDK.
The easiest way to get the VE project sources into your workspace is to fetch the Project Set File (PSF) to your machine, then use Eclipse to import projects from that file. The PSFs are located in this folder in CVS:
Once you have the PSFs, you can import projects into your workspace with
File > Import > Team > Team Project Set
Install Binary requirements
Additionally, build.properties will list any other zipped requirements or update sites from which dependencies must be installed.
Run Local Build
If you are only concerned with compiling VE sources in your workspace in order to generate a patch, you're done!
However, if you'd like to verify that your changes do not break the VE build when run headlessly in Hudson, you will need to run a local build.
First, configure build.properties to point to the correct values for paths (java_home, buildDir, downloadsDir, etc.).
Next, ensure that you're using the correct version of the Eclipse SDK for your platform; by default build.properties will have the Linux PPC version since that's what's used on build.eclipse.org to build VE.
Finally, right-click build.xml and select Run As > Ant Build.
If you configured build.properties correctly, you should then run a local build. Note that if you're on Windows or Mac, you can compile but cannot run the headless JUnit Plugin tests. However, you can run those tests in your Eclipse.