Question

In Eclipse it is possible to create launch configurations in a project, specifying the runtime dependencies from another project. A problem I found was that if you have a multiple project workspace, being possible that each project has its own libraries, it is easy to add explicit dependencies in a secondary project to libraries that are of another project and therefore subject to change.

An example of this problem follows:

proj1
    +-- src  
    +-- lib  
           +-- jar1-v1.0.jar  
           +-- jar2-v1.0.jar  
proj2  
    +-- src  
    +-- proj2-tests.launch

I don’t have a dependency from the code in proj2/src to the libraries in proj1/lib. Nevertheless, I do have a dependency from proj2/src to proj1/src, although since there is an internal dependency in the code in proj1/src to its libraries jar1-v1.0.jar and jar2.v1.0.jar, I have to add a dependency in proj2-tests.launch to the libraries in proj1/lib. This translates to the following ugly lines in proj2-tests.launch:

<listEntry value="<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<runtimeClasspathEntry path="3" projectName="proj1" type="1"/>
"/>
<listEntry value="<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<runtimeClasspathEntry internalArchive="/proj1/lib/jar1-v1.0.jar" path="3" type="2"/>
"/>
<listEntry value="<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<runtimeClasspathEntry internalArchive="/proj1/lib/jar2-v1.0.jar" path="3" type="2"/>
"/>

This wouldn’t be a big problem if there wasn’t the need from time to time to evolve the software, upgrade the libraries and etc. Consider the common need to upgrade the libraries jar1-v1.0.jar and jar2-v1.0.jar to their versions v1.1. Consider that you have about 10 projects in one workspace, having about 5 libraries each and about 4 launch configurations. You get a maintenance overhead in doing a simple upgrade of a library, which normally must imply changes in files for which there wasn’t the need for. Or maybe I’m doing something wrong…

What I would like to state is proj2 depends on proj1 and on its libraries and having this translated to simply that in the *.launch files. Is that possible?

Answer 1

Unless I am mistaken, if you add project1 to the build path of project2, the launcher for project2 will include the right classpath, even if the dependencies of project1 change:

alt text http://img24.imageshack.us/img24/9511/eclipsebuildpath.png

(properties of project2, Java Build Path, tab “Projects”)