object Test extends App { def needPackageConcurrentMap(map: collection.concurrent.Map[Int, Int]) { } def needJavaConcurrent(map: java.util.concurrent.ConcurrentMap[Int, Int]) { } def testConversions() { import collection.convert.ImplicitConversions._ val skiplist = new java.util.concurrent.ConcurrentSkipListMap[Int, Int] val ctrie = new collection.concurrent.TrieMap[Int, Int] needPackageConcurrentMap(skiplist) needJavaConcurrent(ctrie) } def testConverters() { import collection.JavaConverters._ val skiplist = new java.util.concurrent.ConcurrentSkipListMap[Int, Int] val ctrie = new collection.concurrent.TrieMap[Int, Int] needPackageConcurrentMap(skiplist.asScala) needJavaConcurrent(ctrie.asJava) } testConversions() testConverters() }