How do I mock Classes with Scala 3.2, Scalatest 3.2, and Java 18

Question

I have the following code...

@RunWith(classOf[JUnitRunner])
class IdentitySuite extends AnyFunSuite with Matchers {
  test("No Records returned") {
    assert(true)
  }
}

This works fine now I would like to add a mocked Object so I add...

testing {
    suites {
        // Configure the built-in test suite
        test {
            // Use JUnit4 test framework
            useJUnit('4.13.2')
            dependencies {
                // Use Scalatest for testing our library
                implementation 'org.scalatest:scalatest_3:3.2.12'
                implementation 'org.scalatestplus:junit-4-13_3:3.2.12.0'
                implementation 'org.easymock:easymock:4.3'
                implementation 'org.scalatestplus:easymock-4-3_3:3.2.12.0'
                runtimeOnly 'org.scala-lang.modules:scala-xml_3:2.1.0'
            }
        }
    }
}

But when I try to add the mock

@RunWith(classOf[JUnitRunner])
class IdentitySuite extends AnyFunSuite with Matchers {
  test("No Records returned") {
    val cds = EasyMock.createMock(classOf[CoreDataSource])
    assert(true)
  }
}

I get

Caused by: java.lang.reflect.InaccessibleObjectException: Unable to make protected final java.lang.Class java.lang.ClassLoader.defineClass(java.lang.String,byte[],int,int,java.security.ProtectionDomain) throws java.lang.ClassFormatError accessible: module java.base does not "opens java.lang" to unnamed module @40f9161a

I see some old questions that point at downgrading to 15 but that isn't an option in my case.

How do I Mock a Scala class when using Java 18?