Please answer all the following

For the implementation of List class by fixed size array approach, please write codes for the three member functions: constructor, insert, and retrieve (marked red in the class declaration).

The class List is defined as follows:

//The List preserves the order of the elements public class List{ private final T[] items; private int size; // number of items in the list private static final int DEFAULT_CAPACITY=20; //Default constructor public List() { //TO DO } // To check if the list is empty or not public boolean isEmpty() { return size