convert java.util.Map[String, Object] to scala.collection.immutable.Map[String, Any]

Question

How do I convert java.util.Map[String, Object] to scala.collection.immutable.Map[String, Any], so that all values in the original map (integers, booleans etc.) are converted

Answer 1

As VonC says, scala.collections.JavaConversion supports mutable collections only, but you don't have to use a separate library. Mutable collections are derived from TraversableOnce which defines a toMap method that returns an immutable Map:

import scala.collection.JavaConversions._

val m = new java.util.HashMap[String, Object]()
m.put("Foo", java.lang.Boolean.TRUE)
m.put("Bar", java.lang.Integer.valueOf(1))

val m2: Map[String, Any] = m.toMap
println(m2)

This will output

Map(Foo -> true, Bar -> 1)