Chapter 20.6, Problem 20.6.4CP

Explanation of Solution

Comparator interface:

Comparator interface offers the sequence of multiple sorting which offers the compare() method to sort the data.

• It helps the compare the data of different classes.
• The Comparable interface is present in java.util package.
• The lambda expression is used in Comparator interface to simply the code.

Create Comparator interface by using the lambda expression is given below:

//Create object for Collection and compare size of e1 and //e2

(e1, e2) -> e1.size() – e2.size()  

Explanation:

In the above code,

• Create the two objects for Collection such as “e1” and “e2”...