Given an interface for LinkedList - Without using the java collections interface (ie do not import java.util.List, LinkedList, Stack, Queue...) - Create an implementation of LinkedList interface provided - For the implementation create a tester to verify the implementation

Simple linkedlist implementation

please help (looks like a lot but actually isnt, everything is already set up for you below to make it EVEN easier)

help in any part you can be clear

Given an interface for LinkedList
- Without using the java collections interface (ie do not import java.util.List,
LinkedList, Stack, Queue...)
- Create an implementation of LinkedList interface provided
- For the implementation create a tester to verify the implementation of that
data structure performs as expected

Build Bus Route – Linked List
- You’ll be provided a java package containing an interface, data structure,
implementation shell, test harness shell below.
- Your task is to:
o Implement the LinkedList interface (fill out the implementation shell)
o Put your implementation through its paces by exercising each of the
methods in the test harness
o Create a client (a class with a main) ‘BusClient’ which builds a bus
route by performing the following operations on your linked list:
o
§ Create (insert) 4 stations
§ List the stations
§ Check if a station is in the list (print result)
• Check for a station that exists, and one
that doesn’t
§ Remove a station
§ List the stations
§ Add a station before another station
§ List the stations
§ Add a station after another station
§ Print the stations

5 CLASSES TO BEGIN WITH BELOW (edit these classes to fulfill the easy requirements above)
import linkedList.LinkedList;
import linkedList.LinkedListImpl;
import queue.Queue;
import queue.QueueImpl;
import stack.Stack;
import stack.StackImpl;

public class BusClient {

    public static void main(String[] args) {
        // create implementation, then

        System.out.println("-----L I S T  T E S T------");
        
        //listRunTestMethod...
         
        
         }

}

----------

public interface LinkedList {
    public Boolean isItemInList(String thisItem);
        // true if it is, false if not
    public Boolean addItem(String thisItem);
        // true if added, false if it was already there, or an error
    public Integer itemCount();
    public void listItems(); 
    public Boolean deleteItem(String thisItem);
        // true if deleted, false if not there or error
    public Boolean insertBefore(String newItem, String itemToInsertBefore);
    public Boolean insertAfter(String newItem, String itemToInsertAfter);
    
    
    
    //EC
    public void sort();
        // ascending alphanumeric sort; nothing fancy but ALTERS THE LIST, DOES NOT COPY.
}

// Implement this interface using class ListItem
//  Also implement the tester in this package.

----------

public class LinkedListImpl implements LinkedList {

    
    private ListItem head;
    
    @Override
    public Boolean isItemInList(String thisItem) {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public Boolean addItem(String thisItem) {
        
        
        //get the last item:
        
        ListItem lastItem = head;
                
        if (head == null)
            lastItem =  null;
        else {
            lastItem = head;
                    
            //last node points to null
            while (lastItem.next != null)
                    lastItem = lastItem.next;
            }
            
        
        
        
        // create a ListItem, if head is null, set the newItem  
            // to be the head
            // else, set the head.next to the newItem
            
        ListItem newItem = new ListItem(thisItem);

        if (head == null) {
            head = newItem;
        } else {
            //head.next = newItem;
            lastItem.next = newItem;
            
        }
         
        return true;
         
    }

    @Override
    public Integer itemCount() {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public void listItems() {
        ListItem tmp = head;
        while(tmp != null) {
            System.out.println("current data: " +  tmp.data);
            tmp = tmp.next;
        }
        
    }

    @Override
    public Boolean deleteItem(String thisItem) {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public Boolean insertBefore(String newItem, String itemToInsertBefore) {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public Boolean insertAfter(String newItem, String itemToInsertAfter) {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public void sort() {
        // TODO Auto-generated method stub
        
    }
    
}

----------

public class LinkedListTester {

    public static void main(String[] args) {

        LinkedList l = new LinkedListImpl();
        l.addItem("bearded dragon");
        l.addItem("iguana");
        l.addItem("turtle");
        
        
        l.listItems();
        
        
    }

}

---------- 

public class ListItem {
    public String data;
    public ListItem next;
    
    public ListItem(String data) {
        this.data = data;
        this.next = null;
    }
}