Since "new X(a, b) {...}" is equivalent to "new X(a, b, {...})", we need to generate adapter classes used for subclassing/implementing Java types in Nashorn in such a manner that the adapter class constructors take the ScriptObject/ScriptFunction arguments as their last argument, not their first argument (as they do now). Note that this will make it impossible to generate variable arity constructors - a variable arity constructor in the extended class will appear as a fixed-arity constructor taking an array in the adapter subclass.