This issue was reported by Axel Faust via https://twitter.com/ReluctantBird83/status/679600616595918848 (see also JI-9027774).

Test case is here -> http://fpaste.org/304235/50864308/

Test case copied here for convenience:

    var nr = Packages.java.lang.Double.valueOf(2.5);
    var prop = 'int';
    print(nr[prop + 'Value']); // yields undefined instead of method handle for intValue()