Write a class named CustomList.java that is a subclass of CMSC$256$LinkedList.java. The CustomList class must contain the following methods:

$/**$

$*$ Returns the middle element of the$$

$*$ If the number of elements in the list is even, there will be two middle nodes,

$*$ so return the second one.

$*$ For example, if the list contains $[23,34,98,22,12,76,81],$ the

$*$ method returns $22$

$*$ If the list contains $[23,34,98,22,12,76,81,101],$ the

$*$ method returns $12$

$*$ @throws$$ IllegalStateException if the list is empty or null

$*$ @return an instance T

$*/$

public T getMiddleElement$()$

$$

$/**$

$*$ Returns the first half of the list.

$*$ If the number of elements in the list is odd, include the extra element.

$*$ For example if the list contains $[23,34,98,22,12,76,81],$ the

$*$ method returns a list $[23,34,98,22]$

$*$

$*$ @return an instance of a class that implements the ListInterface

$**/$

public ListInterface getFirstHalf$()$

$$

$/**$

$*$ Returns the last half of the list.

$*$ If the number of elements in the list is odd, exclude the extra element.

$*$ For example if the list contains $[23,34,98,22,12,76,81],$ the

$*$ method returns a list containing $[12,76,81]$

$*$

$*$ @return an instance of a class that implements the ListInterface

$**/$

public ListInterface getLastHalf$()\{$

$$

$/**$

$*$ Returns a List that consists of all and only the elements

$*$ in every fourth positions $($i$.$e$.,$ fourth, eighth, and so on$)$ in

$*$ the current string, in the same order as the current list.

$*$ If the list contains $[23,34,98,22,12,76,81,101],$ the

$*$ method returns $[22,101]$

$*$ @return an instance of a class that implements the ListInterface

$*/$

public ListInterface getEveryFourthElement$()$

$$

$/**$

$*$ @return true if there are any elements in the list that occur twice

$*$ false otherwise

$*$ Note: if an element occurs more that twice, do not include it

$*$ If the list contains $[23,34,98,22,12,76,81,101,12,23,33,23],$ the

$*$ method returns true

$*/$

public boolean hasDuplicates$()$

$$

$/**$

$*$ @return an instance of a class that implements the ListInterface that

$*$ contains those elements in this list that appear more than once.

$*$ If the list contains $[23,34,98,22,12,76,81,101,12,23,33,23],$ the

$*$ method returns $[23,12]$

$**/$

public ListInterface getAllMultiples$()\{$

$$

$/**$

$*$ Alters the list by deleting any elements that occur twice in the list.

$*$ Elements that occur more than $2$ times remain in the list.

$*$ If the list contains $[23,34,98,22,12,76,81,101,12,23,33,23],$ the

$*$ method removes $12$ and the list becomes $[23,34,98,22,76,81,101,23,33,23]$

$*/$

public void removeAllDuplicates$()$

$$

$/*$

$*$ Removes the nth node from the end of the list

$*$ For example, if the list contains $[43,68,11,5,69,37,70]$ and $1$ is passed to the method

$*$ a value of $70$ is returned and the list becomes $[43,68,11,5,69,37]$

$*$ @return the element from the position that was removed

$**/$

public T removeNthNodeFromEnd$($int n$)$