Lambda expressions usage

A lambda expression can be used in many different situations, including:

• Assigned to a variable
• Passed as a parameter
• Returned from a function or method

We will demonstrate how each of these is accomplished and then elaborate on the use of functional interfaces. As you may remember from Chapter 1, Getting Started with Functional Programming, a functional interface is an interface that has one and only one abstract method.

Consider the forEach method supported by several classes and interfaces, including the List interface. In the following example, a List interface is created and the forEach method is executed against it. The forEach method expects an object that implements the Consumer interface. This will display the three cartoon character names:

    List<String> list = Arrays.asList("Huey", "Duey", "Luey");
    list.forEach(/* Implementation of Consumer Interface*/);

More specifically, the forEach method expects an object that implements...