How I Came to Hate Orbit

Orbit is an Eclipse project which contains IP clean OSS code to be used in Eclipse projects.

Why is that important? Well, IP clean means that big companies who consume Eclipse code, can use it safely (their lawyers have to check the EPL once and after that, their developers can use any code they can find on eclipse.org).

Now, Eclipse writes a lot of source code but not everything. commons-io, for example, contains a lot of code which would be really cool to have for Eclipse projects.

Orbit was created to have just that: Copies of OSS code from all kinds of places relicensed under the EPL. Sweet.

Enter stage: maven.eclipse.org

The idea behind maven.eclipse.org is to provide projects outside of the Eclipse foundation a place where they can find Eclipse’s OSGi bundles as Maven artifacts (which are easier to consume when you build your projects with Maven). Sweet 2.

To make the Eclipse bundles available on maven.eclipse.org, I need to convert them. Part of that process is to assign each Eclipse bundle (which has bundle ID and a version) a Maven coordinate (which consists of group ID, artifact ID and version). That’s not always simple but I’ve found a rule that works pretty well.

If it wasn’t for Orbit.

Orbit contains bundles which you can also find on Maven central. One example is commons-io.

And Orbit didn’t simply copy the JAR from Maven Central – they changed it. In this case, the changes are purely for legal reasons (EPL license, moved a couple of files around). Not a big problem here. I could map the two to the same coordinate – except that you would sometimes build software which contains code licensed by Apache and sometimes code which is licensed by EPL. Worse, some other code might be under the viral GPL on Maven Central – linking that could turn your project into open source! Not a problem for most developers but it could be a problem for your legal department and guess which head is going to roll?

But there is more.

Let’s have a look at … org.apache.batik.pdf. This is a fragment of the Batik’s rasterizer JAR from Maven Central. In this case, we have several issues:

• Orbit has split a single artifact from Maven Central into several Orbit bundles. Which bundle should get the same coordinate as the original Maven Artifact?
• The Orbit bundle also contains code from commons-io and commons-logging. So it pollutes your classpath with classes that you don’t expect. Worse, someone (not the Eclipse guys) removed “unnecessary” methods from some classes copied from commons-io. So if the compiler sees this JAR on the classpath, you will get errors for many methods in the class IOUtils. Bad.
• Some Orbit bundles have bugs fixed but the version hasn’t been changed – only the qualifier changed which works if you use OSGi to build your classpath but Maven doesn’t. A couple of bundles from org.apache.batik are among them (bug 329376).

While it might make sense from Orbit’s point of view to do this, it makes my life a bit complicated.