change the type of the handler function, and go down the rabbit hole a bit. Add a Procedure2[T1,T2] to the Java API, and add JavaEventHandler that gives access from java to the EventHandler, add docs for configuring the handler in declarative Supervision for Scala and Java.

akka-actor/src/main/scala/akka/japi/JavaAPI.scala

@@ -20,6 +20,12 @@ trait Procedure[T] {
   def apply(param: T): Unit
 }
 
+/** A Procedure is like a Function, but it doesn't produce a return value
+ */
+trait Procedure2[T1,T2] {
+  def apply(param: T1, param2:T2): Unit
+}
+
 /**
  * An executable piece of code that takes no parameters and doesn't return any value.
  */