Java <-> Scala interop: transparent List and Map conversion

Question

I am learning Scala and I have a Java project to migrate to Scala. I want to migrate it by rewriting classes one-by-one and checking that new class didn\'t break the project

Answer 1

Here are some quick examples using Jorge Ortiz's scalaj-collection library:

import org.scala_tools.javautils.Implicits._

val sSeq = java.util.Collections.singletonList("entry") asScala
// sSeq: Seq[String] 
val sList = sSeq toList // pulls the entire sequence into memory
// sList: List[String]
val sMap = java.util.Collections.singletonMap("key", "value") asScala
// sMap: scala.collection.Map[String, String]

val jList = List("entry") asJava
// jList: java.util.List[String]
val jMap = Map("key" -> "value") asJava
// jMap: java.util.Map[String, String]

the javautils project is available from the central maven repository