Get ParameterizedType from scala Type?

Question

Useful, scala universe.typeOf stores type parameters for a class.

import scala.reflect.runtime.universe._ case class X[T:TypeTag]() { val t = typeOf[T] // eg Seq[Int] Holds type parameters val clz:Class[_] = runtimeMirror(this.getClass.getClassLoader).runtimeClass(t.typeSymbol.asClass) } X[Seq[Int]]().t // Seq[Int] X[Seq[Int]]().clz // Seq :-( 

Java ParameterizedType contains the same information that has not been erased. How to convert scala type to Java ParameterizedType?

 import scala.reflect.runtime.universe._ case class X[T:TypeTag]() { val clz:Class[_] = runtimeMirror(this.getClass.getClassLoader).runtimeClass(typeOf[T].typeSymbol.asClass) } 

Answer 1

  private def parameterizedType(paramType: Type): java.lang.reflect.Type = { val typeConstructor = currentMirror.runtimeClass(paramType) val innerTypes = paramType.typeArgs.map(parameterizedType).toArray if (innerTypes.isEmpty) { typeConstructor } else { new ParameterizedType { override def getRawType: reflect.Type = { typeConstructor } override def getActualTypeArguments: Array[reflect.Type] = { innerTypes } override def getOwnerType: reflect.Type = { null } } } } def makeType[T : TypeTag]: reflect.Type = { parameterizedType(typeOf[T]) } 

This seems to be a trick. Basically just repeating through parameterized types and converting it to an object of a parameterized type java