Force Java to Scala explicit type casting on unknown java.util.Map type

casting, java, scala, scala-collections, type-conversion

Solution

This works for me

val javaMap : java.util.Map[_, _] = null
val scalaMap = javaMap.asScala.toMap.asInstanceOf[Map[String, Double]]

Remember to include

import scala.collection.JavaConverters._

Problem

I recently worked with some Java collection (well know JavaFX), and I had recently a problem (a consequence of this other problem posted here). One of the JavaFX interfaces I need only accepts `java.util.Map`, equal to `Map[_,_]` in Scala. I make a conversion with `asInstanceOf`, but after computation, if I want to transform my `java.util.Map[_,_]` to force the cast into a real Scala type safe `Map[String,Double]` I use in all my program, how can I do it? I tried `java.conversions._` and `asInstanceOf` methods without success. ``` //return a java.util.Map val row: java.util.Map[_,_] = c.getTableView().getItems().get(0) //I need a Map[String,Double] in my program val parameters = row.toMap[String,Double] ```

Original source