Stream method ________ maps objects to double values and returns a DoubleStream. The method receives an object that implements the functional interface ToDoubleFunction (package java.util.function).
A) doubleMap
B) toDouble
C) mapToDouble
D) toDoubleStream

Question

Quizplus · Accepted Answer

The correct method to map objects to double values and return a DoubleStream is mapToDouble, which takes a ToDoubleFunction as an argument. Option A (doubleMap) and option D (toDoubleStream) are not valid methods in the Java streams API. Option B (toDouble) does exist in the API, but it converts a primitive value to a Double object, rather than mapping an object to a primitive double.

Stream Method ________ Maps Objects to Double Values and Returns