IllegalAccessError on jdk-17 in a project using repast

currently I am working on a java project that uses the repast java library (repast.jar, colt.jar and trove.jar). The project works fine with jdk-11, but currently, I am trying to migrate to jdk-17 and I am not able to run the project because of the next exception:

Exception in thread "main" java.lang.IllegalAccessError: class com.go.trove.classfile.AccessFlags tried to access private method 'void java.lang.reflect.Modifier.<init>()' (com.go.trove.classfile.AccessFlags is in unnamed module of loader 'app'; java.lang.reflect.Modifier is in module java.base of loader 'bootstrap')
    at com.go.trove.classfile.AccessFlags.<init>(AccessFlags.java:75)
    at com.go.trove.classfile.ClassFile.<init>(ClassFile.java:160)
    at com.go.trove.classfile.ClassFile.<init>(ClassFile.java:138)
    at uchicago.src.sim.util.ByteCodeBuilder.generateBasicAction(Unknown Source)
    at uchicago.src.sim.engine.ActionUtilities.createActionFor(Unknown Source)
    at uchicago.src.sim.engine.ScheduleBase.scheduleActionBeginning(Unknown Source)
    at uchicago.src.sim.engine.ScheduleBase.scheduleActionBeginning(Unknown Source)

I remember reading that in a recent version of java some changes on the reflection API occurred. Would this be a possible cause?

Any idea of how to solve it? Is that hard to solve?

Thanks so much!

Solution

Yea ...

The Tea / Trove project is ancient code that hasn't been maintained by the original developers (Disney Corp!). There is fork on Github at https://github.com/teatrove/teatrove ... but that has had no activity since 2013 either. Not promising.

As to your problem. Well it seems that the original designers decided to make the org.teatrove.trove.classfile.Modifiers a subclass of java.lang.reflect.Modifier.

The problem is that Modifier used to have a default public constructor ... but in Java 14 they deprecated this constructor (javadoc). In Java 17 there is now a private no-args constructor. That means that when Trove attempts to create a Modifiers instance on Java 17, it fails with a binary compatibility error.

One way to solve this would be to modify Trove so that Modifiers is no longer a subclass of Modifier. I don't know how feasible that would be. The feasibility will depend on whether the codebase makes use of the fact that Modifiers is a subtype of Modifier. That would be for you to investigate ...

If you take this approach, be a good citizen and submit your changes as a pull request against the "TeaTrove" codebase on Github.

Another approach would be to look for a replacement for the Trove dependency in your application. Again, without knowing how / why you are using Trove, it is difficult to suggest an alternative.

Your application's dependency may be due to your using an old version of Repast. I can't find any information on old Repast versions ... but this suggests another approach would be to upgrade to a newer Repast version that (hopefully¹) avoids the Trove dependency.

Finally, given that the Repast developers still recommend Java 11 for the most recent versions of Repast, you could just stick with that.

^{1 - The Repast codebase doesn't use a modern build tool like Maven or Gradle that take a declarative approach to dependencies². Instead they have snarfed copies of the dependency JARs and put them into their source repo. This makes dependency analysis difficult.

2 - See https://github.com/Repast/repast.simphony/issues/4}