scala libraryDependencies += "org.scalamock" %% "scalamock" % "4.4.0" % Test scala import org.scalamock.scalatest.MockFactory import org.scalatest.flatspec.AnyFlatSpec class MyScalaClass(mockedJavaClass: MyJavaClass) { def myMethod(): String = { mockedJavaClass.someMethod() } } class MyTest extends AnyFlatSpec with MockFactory { "MyScalaClass" should "call someMethod on MyJavaClass" in { val mockedJavaClass = mock[MyJavaClass] val myScalaClass = new MyScalaClass(mockedJavaClass) (mockedJavaClass.someMethod _).expects().returns("Mocked response") assert(myScalaClass.myMethod() == "Mocked response") } }