We now determine initial values for primitive parameters in Kotlin constructors that are absent (null) and defaulted. We default all Java primitive types to their initial zero value to prevent possible NullPointerExceptions. Kotlin defaulting uses a bitmask to determine which parameter should be defaulted but still requires the appropriate type.
Previously, null values were attempted to cast/unbox and caused NullPointerException even though they had default values through Kotlin assigned.
Original pull request: #255.
cf5af6a971