Workaround for notserializable exception when converting Scala map to Java Map

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As described in this Github issue, Scala Maps that are wrapped as Java Maps are not serializable because scala.collection.convert.Wrappers$MapWrapper is not serializable.

This issue was fixed in Scala 2.12, but I have to use 2.11 for various reasons. So what is a good workaround for converting a Scala Map to a Java Map without having this serialization error? I have no choice but to return a java map from this function.

My code looks like this:

import scala.collection.JavaConverters.mapAsJavaMapConverter

def doSomethingCool(): util.Map[String, String] = {

    // ... Cool processing here ...
    // Return results as a Java Map
    myScalaMap.asJava
}

I feel like there should be a simple way to work around this issue, but I haven't been able to figure it out...

java scala
1 Answers

It is possible to copy a wrapped map with the java.util.HashMap's copy constructor.

import scala.collection.JavaConverters.mapAsJavaMapConverter

def doSomethingCool(): util.Map[String, String] = {

    // ... Cool processing here ...
    // Return results as a Java Map
    new java.util.HashMap[String, String](myScalaMap.asJava)
}
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