def new_instance(cls, classname, length):
        """
        Creates a new array with the given classname and length; initial values are null.

        :param classname: the classname in Java notation (eg "weka.core.DenseInstance")
        :type classname: str
        :param length: the length of the array
        :type length: int
        :return: the Java array
        :rtype: JB_Object
        """
        return javabridge.static_call(
            "Ljava/lang/reflect/Array;",
            "newInstance",
            "(Ljava/lang/Class;I)Ljava/lang/Object;",
            get_jclass(classname=classname), length)