@@ -0,0 +1,474 @@
+//this is a simple queue class%0A%0Aclass Queue%7B%0A    Node first, last;%0A    void enqueue(Object item) %7B%0A        if(!first) %7B%0A            back = new Node(item);%0A            first = back;%0A        %7D else %7B%0A            back.next = new Node(item);%0A            back = back.next;%0A        %7D%0A    %7D%0A    Node dequeue(Node n) %7B%0A        if (first != null) %7B%0A            Object item = first.data;%0A            first = first.next;%0A            return item;%0A        %7D%0A        return null;%0A    %7D%0A%7D%0A

Create Queue.java