Hi I'm trying to use multiple versions of a package that has an identical classpath. Is there a way to relocate each version of these plugins to custom locations (like org.example -> org.example.v1)? I know there is the shadow plugin but it seems to only support relocating the entirety of that classpath which seems like it would relocate all the versions to the same spot. Is there another way to do this? Thanks!

What code is calling into the different version and how does it know which version ends up running?

I'm designing a wrapper that will take the version number as input and output the method or object in question. Depending on the implementation details might make specific wrapper methods for the method/object api calls I'm using to account for changes in variable naming

So the code that calls your lib is in a different jar file, right?

The code is part of my main class with jar dependencies. I need to create an object that has methods that will either call one package version or the other. Normally I'd use class loaders but I'm in a graalvm native image which won't have the JVM and class loaders so I'd have to do everything in the build phase so the only option I see is to move each jar version to its own unique location on the classpath

Then relocate them each one separately?

Yeah pretty much put them into separate class locations so if each had a classpath of org.example.* it'd be org.example.v1.*

I think you mean

package name

instead of

classpath

?

Yeah I mean how it's api calls that you import appears in terms of the classpath

So you have

lib-1.jar

containing

com.example.Hello.class

and

lib-2.jar

containing the same symbol

com.example.Hello.class

except with a different implementation

Yeah that's correct

Now you can relocate

lib-1.jar

with

relocate("com.example", "com.example.v1")

and

lib-2.jar

with

relocate("com.example", "com.example.v2")

Technically each package is split up into multiple jars with .so files connected through JNI

Ah, JNI might make things a bit more complicated but I know nothing about JNI

Would that work with them both being com.example as based on my understanding it'd do that on everything under that classpath

I'm not sure I follow. If you do what I suggested above, you will end up with: •

lib-1-shadow.jar

containing

com.example.v1.Hello

•

lib-2-shadow.jar

containing

com.example.v2.Hello

Yeah wasnt sure if I can do it with just the jars

Yea, this is probably what you want. If you add both

lib-1.jar

and

lib-2.jar

to the dependencies of your project it's too late

Especially with JNI in play I doubt any relocation will work. You would probably need to have separate processes for the libs and dispatching calls to those or something like that.

Yea JNI sounds not easy

Possibly I'm not too familiar with what the .so files perform, I suppose that's where manual byte manipulation like with ASM?

ASM can deal with your

.jar

files. The

.so

is probably a lot more involved because depending the OS, it's a different file format, etc....

Gotcha are there any other alternatives to handle the .so files?

Even if you could change the package name in the native lib. You would also need to change its identity and loading, because you cannot load a native library twice in the lifetime of a JVM.