using truezip in shadowJar built with gradle

Question

i have a shadowJar compiled with gradle which uses truezip to get some files out of a zip-file.

i get this exception using it:

Exception in thread "main" java.util.ServiceConfigurationError: file (Unknown file system scheme! May be the class path doesn't contain the respective driver module or it isn't set up correctly?)
    at de.schlichtherle.truezip.fs.FsAbstractCompositeDriver.newController(FsAbstractCompositeDriver.java:33)
    at de.schlichtherle.truezip.fs.FsDefaultManager.getController0(FsDefaultManager.java:95)
    at de.schlichtherle.truezip.fs.FsDefaultManager.getController(FsDefaultManager.java:78)
    at de.schlichtherle.truezip.file.TBIO.getInputSocket(TBIO.java:280)
    at de.schlichtherle.truezip.file.TFileInputStream.newInputStream(TFileInputStream.java:101)
    at de.schlichtherle.truezip.file.TFileInputStream.<init>(TFileInputStream.java:95)

i set a archiveDetector like this:

final TArchiveDetector ad = new TArchiveDetector("foo", new ZipDriver(IOPoolLocator.SINGLETON));
TConfig.get().setArchiveDetector(ad);

the exception is thrown when i want to make an input-stream like this:

final TFileInputStream is = new TFileInputStream(thefile);

as far as i can tell the shadowJar contains all necessary classes, but maybe something is missing?

how would i know which class, which package is missing? what else could cause this?

running it out of eclipse works...

thanks for any help.

Answer 1

That's a common issue when creating an uber-JAR: The individual entries at META-INF/services/* need to get appended. However, by default, many tools simply overwrite them when creating the uber-JAR. As a result, the ServiceLoader class cannot find all necessary plugins (e.g. for file system drivers), which is what this exception is complaining about.

So you need to fix the configuration of the tool which creates your uber-JAR. If you are using Maven with the maven-shade-plugin, then you can simply add the ServicesResourceTransformer - see https://maven.apache.org/plugins/maven-shade-plugin/examples/resource-transformers.html#ServicesResourceTransformer.

Another option is to not use an uber-JAR at all, which is the default when using Maven.

Eclipse can read Maven projects and establish its meta data from it, so maybe you want to consider converting your project to use Maven - if you haven't already.

Answer 2

I had the same problem. After some research i found the following solution:

In your build.gradle add the following:

shadowJar {
    mergeServiceFiles()
}