AbstractMethodError at runtime when casting Scala classes from different jars

(disclamer I'm quite new in scala).

I'm trying to create a dynamic plugin system for my scala project. I have a base class in library (on my own maven repo)

package my.project.base
abstract class BasePlugin { val inputs: Map[Regex, (Int, Int, Boolean)] }

and a plugin compile as JAR (using SBT to resolve BaseModule)

package my.plugin
import my.project.base.BasePlugin
class testPlugin1 extends BasePlugin { val inputs = Map("_default0".r, (1, 1, true)) }

In the engine project, which also resolve BaseModule from Maven. I tried the following:

import my.project.base.BasePlugin
import java.io.File
import java.net.{URL, URLClassLoader}
import org.clapper.classutil.{ClassFinder, ClassInfo}

object PluginManager {
  def registerPlugin(file: File): Unit = {
    val finder = ClassFinder(Seq(file))
    val classes = finder.getClasses

    // Getting moduleInfo Object
    val pluginsInfo = ClassFinder.concreteSubclasses("my.project.base.BasePlugin", classes.iterator)

    if (pluginsInfo.hasNext) {
       val classLoader: ClassLoader = new URLClassLoader(Array(file.toURI.toURL), getClass.getClassLoader)
       val plugin1 = pluginsInfo.next

       val pluginClass = classLoader.loadClass(plugin1.name)
       val pluginIns = pluginClass.newInstance

       val baseIns = pluginIns.asInstanceOf[BasePlugin]
       println(test1Ins.inputs.toMap)

It crashes at runtime with :

An exception or error caused a run to abort: my.project.BasePlugin.inputs()Lscala/collection/immutable/Map; 
java.lang.AbstractMethodError: my.project.BasePlugin.inputs()Lscala/collection/immutable/Map;
    at my.engine.PluginManager$.registerPlugin(Module.scala:87)
    at my.engine.test.PluginLoadingTest$$anonfun$1.apply$mcV$sp(PluginLoadingTest.scala:18)
    at my.engine.test.PluginLoadingTest$$anonfun$1.apply(PluginLoadingTest.scala:16)
    at my.engine.test.ModuleLoadingTest$$anonfun$1.apply(PluginLoadingTest.scala:16)
    at org.scalatest.Transformer$$anonfun$apply$1.apply$mcV$sp(Transformer.scala:22)
    at org.scalatest.OutcomeOf$class.outcomeOf(OutcomeOf.scala:85)
    at org.scalatest.OutcomeOf$.outcomeOf(OutcomeOf.scala:104)
    at org.scalatest.Transformer.apply(Transformer.scala:22)
    at org.scalatest.Transformer.apply(Transformer.scala:20)
    at org.scalatest.FlatSpecLike$$anon$1.apply(FlatSpecLike.scala:1647)
    at org.scalatest.Suite$class.withFixture(Suite.scala:1122)
    at org.scalatest.FlatSpec.withFixture(FlatSpec.scala:1683)
    at org.scalatest.FlatSpecLike$class.invokeWithFixture$1(FlatSpecLike.scala:1644)
    at org.scalatest.FlatSpecLike$$anonfun$runTest$1.apply(FlatSpecLike.scala:1656)
    at org.scalatest.FlatSpecLike$$anonfun$runTest$1.apply(FlatSpecLike.scala:1656)
    at org.scalatest.SuperEngine.runTestImpl(Engine.scala:306)
    at org.scalatest.FlatSpecLike$class.runTest(FlatSpecLike.scala:1656)
    at org.scalatest.FlatSpec.runTest(FlatSpec.scala:1683)
    at org.scalatest.FlatSpecLike$$anonfun$runTests$1.apply(FlatSpecLike.scala:1714)
    at org.scalatest.FlatSpecLike$$anonfun$runTests$1.apply(FlatSpecLike.scala:1714)
    at org.scalatest.SuperEngine$$anonfun$traverseSubNodes$1$1.apply(Engine.scala:413)
    at org.scalatest.SuperEngine$$anonfun$traverseSubNodes$1$1.apply(Engine.scala:401)
    at scala.collection.immutable.List.foreach(List.scala:381)
    at org.scalatest.SuperEngine.traverseSubNodes$1(Engine.scala:401)
    at org.scalatest.SuperEngine.org$scalatest$SuperEngine$$runTestsInBranch(Engine.scala:390)
    at org.scalatest.SuperEngine$$anonfun$traverseSubNodes$1$1.apply(Engine.scala:427)
    at org.scalatest.SuperEngine$$anonfun$traverseSubNodes$1$1.apply(Engine.scala:401)
    at scala.collection.immutable.List.foreach(List.scala:381)
    at org.scalatest.SuperEngine.traverseSubNodes$1(Engine.scala:401)
    at org.scalatest.SuperEngine.org$scalatest$SuperEngine$$runTestsInBranch(Engine.scala:396)
    at org.scalatest.SuperEngine.runTestsImpl(Engine.scala:483)
    at org.scalatest.FlatSpecLike$class.runTests(FlatSpecLike.scala:1714)
    at org.scalatest.FlatSpec.runTests(FlatSpec.scala:1683)
    at org.scalatest.Suite$class.run(Suite.scala:1424)
    at org.scalatest.FlatSpec.org$scalatest$FlatSpecLike$$super$run(FlatSpec.scala:1683)
    at org.scalatest.FlatSpecLike$$anonfun$run$1.apply(FlatSpecLike.scala:1760)
    at org.scalatest.FlatSpecLike$$anonfun$run$1.apply(FlatSpecLike.scala:1760)
    at org.scalatest.SuperEngine.runImpl(Engine.scala:545)
    at org.scalatest.FlatSpecLike$class.run(FlatSpecLike.scala:1760)
    at org.scalatest.FlatSpec.run(FlatSpec.scala:1683)
    at org.scalatest.tools.SuiteRunner.run(SuiteRunner.scala:55)
    at org.scalatest.tools.Runner$$anonfun$doRunRunRunDaDoRunRun$3.apply(Runner.scala:2563)
    at org.scalatest.tools.Runner$$anonfun$doRunRunRunDaDoRunRun$3.apply(Runner.scala:2557)
    at scala.collection.immutable.List.foreach(List.scala:381)
    at org.scalatest.tools.Runner$.doRunRunRunDaDoRunRun(Runner.scala:2557)
    at org.scalatest.tools.Runner$$anonfun$runOptionallyWithPassFailReporter$2.apply(Runner.scala:1044)
    at org.scalatest.tools.Runner$$anonfun$runOptionallyWithPassFailReporter$2.apply(Runner.scala:1043)
    at org.scalatest.tools.Runner$.withClassLoaderAndDispatchReporter(Runner.scala:2722)
    at org.scalatest.tools.Runner$.runOptionallyWithPassFailReporter(Runner.scala:1043)
    at org.scalatest.tools.Runner$.run(Runner.scala:883)
    at org.scalatest.tools.Runner.run(Runner.scala)
    at org.jetbrains.plugins.scala.testingSupport.scalaTest.ScalaTestRunner.runScalaTest2(ScalaTestRunner.java:138)
    at org.jetbrains.plugins.scala.testingSupport.scalaTest.ScalaTestRunner.main(ScalaTestRunner.java:28)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144)


Process finished with exit code 0

I'd tried with abstract class and class in the same file and it works. am I doing something wrong ?