I'm trying to import a .jar, located in my project's libs folder

build.gradle:
 

{
  repositories {...}
  dependencies {
      	minecraft 'net.minecraftforge:forge:1.19.2-43.2.11'
      	implementation files("libs/rbullet.jar")
  }
}

That way I manage to call a constructor from a class of `rbullet`, but when I open the game, I get the following error:

 

	Caused by 1: java.lang.NoClassDefFoundError: com/robsutar/rbullet/CorpoRigido
		at com.example.examplemod.ExampleMod.<init>(ExampleMod.java:63) ~[%23193!/:?] {re:classloading}
		at jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[?:?] {}
		at jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:77) ~[?:?] {}
		at jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[?:?] {}
		at java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:499) ~[?:?] {}
		at java.lang.reflect.Constructor.newInstance(Constructor.java:480) ~[?:?] {}
		at net.minecraftforge.fml.javafmlmod.FMLModContainer.constructMod(FMLModContainer.java:68) ~[javafmllanguage-1.19.2-43.2.11.jar%23189!/:?] {}
		at net.minecraftforge.fml.ModContainer.lambda$buildTransitionHandler$10(ModContainer.java:121) ~[fmlcore-1.19.2-43.2.11.jar%23192!/:?] {}
		at java.util.concurrent.CompletableFuture$AsyncRun.run(CompletableFuture.java:1804) ~[?:?] {}
		at java.util.concurrent.CompletableFuture$AsyncRun.exec(CompletableFuture.java:1796) ~[?:?] {}
		at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:373) ~[?:?] {}
		at java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1182) ~[?:?] {}
		at java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1655) ~[?:?] {}
		at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1622) ~[?:?] {}
		at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:165) ~[?:?] {}

it's like examplemod just to demonstrate that it's not a compatibility issue with anything else, but I've tried putting it in my main project and I'm getting the same error

rbullet is a project I created, which has only one class `CorpoRigido`, and I can reference this class, using gradle in the same way, without any problem in other projects that are not of the forge architecture (new java project). Am I forgetting something?

Forge won't load things unless they are mods or part of a mod.

https://forge.gemwire.uk/wiki/Dependencies

https://forge.gemwire.uk/wiki/Jar-in-Jar