Building Java projects with circular imports in Eclipse

Question

I have a legacy Java (not my native language) app that I'm trying to build in Eclipse Galileo.

As it's not my own, I can't speak to the quality of the design, but I am coming across a number of instances where I'll have something like this:

In a project called, say, "lib_a", I'll have a file containing this:

import com.acme.lib_b.onething;

Project "lib_b" on the other hand, will contain:

import com.acme.lib_a.anotherthing;

Of course, the problem is that one project can't be built because the errors prevent me from creating a .jar file that can be added as an external archive to the other project, and vice versa.

It seems to me that this must be a fairly common occurence in building Java applications. Rewriting it from scratch is not an option here, so I'd like to know "what other folks do."

Answer 1

You can link projects in eclipse, so you're essentially declaring one project as a dependency of another, just like declaring a jar.

Project:-> Properties -> click on the "projects" tab, click "add", and you'll have the option of any open project.Additionally eclipse tracks these so that when you open "A" linked project "B" opens.

Answer 2

I'd just merge them as a single project.

If you cant use A without B and you cant use B without A having separate JAR files doesn't seem very useful.

Answer 3

Maybe if onething and anotherthing aren't core parts of each project (e.g., utility classes), then you could move one into the other project to make the references one-way, or create a common util.jar.

Otherwise I would merge the projects if they are interrelated to a great extent.

Answer 4

Basically a sign of poor design. Possible solutions

• there are common parts in the 2 libs that should be refactored into a "common" library
• both libraries are really 2 halves of the same library and should be combined
• one library is relying on the "internals" of another library and some interfaces should be introduced to break this bad dependency