Often times the order in which projects are built is important. For example, if one project requires the Java classes which were defined in another project, the first project must be built after its prerequisite classes have been built. The Workbench allows users to explicitly define the order in which projects are built. Alternatively, users can let the platform compute the build order by interpreting project references as prerequisite relationships. The build order is applied for both building the entire workspace or for a group of projects.
You can change this order on the Build Order preferences page. Initially the Use Defaults option is on, in which case the platform computes the build ordering. Turning off this option enables access to the projects list, the ordering of which can be manipulated. Select projects and use the Up, Down, and Remove buttons to change the build order. Use the Add button to add projects that are not in the list to the build order.
Here is what the Build Order preference page looks like:
