A$)$ Use the KWArrayList in your application with the following modification:

$-$ The add method should not insert a new item if it already exists.

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B$)$ Write a class called ListApplication having the following methods:

$-$ In the main method: create objects called listOfStudents of type KWArrayList, allow the user to read the information of n students and add them to the list, display the listOfStudents before sorting and after sorting, and search a given student in the listOfStudents.

$-$Define a method called sortStudentList that receives a list of type KWArrayList, sort the elements based on their sid.

$-$ Define a method called exclude that receives two parameters L$1$ and L$2$ of type KWArrayList, and excludes from L$1$ every student s if s is in L$2.$