Java implementation of the queue class

Java implementation of the queue class

ImportJava.util.Iterator;Importjava.util.NoSuchElementException;ImportJava.util.Scanner; Public classQueue<item>ImplementsIterable<item> {    Private intN; PrivateNode<item>First ; PrivateNode<item>Last ; Private Static classNode<item> {        Privateitem Item; PrivateNode<item>Next; }     PublicQueue () { First=NULL; Last=NULL; N= 0; }     Public BooleanIsEmpty () {returnFirst = =NULL; }     Public intsize () {returnN; }     PublicItem Peek () {if(IsEmpty ())Throw NewNosuchelementexception ("Queue underflow"); returnFirst.item; }     Public voidEnqueue (item item) {Node<Item> Oldlast =Last ; Last=NewNode<item>(); Last.item=item; Last.next=NULL; if(IsEmpty ()) First =Last ; ElseOldlast.next =Last ; N++; }     PublicItem dequeue () {if(IsEmpty ())Throw NewNosuchelementexception ("Queue underflow"); Item Item=First.item; First=First.next; N--; if(IsEmpty ()) last =NULL; returnitem; }     PublicString toString () {StringBuilder s=NewStringBuilder ();  for(Item Item: This) S.append (item+ " "); returns.tostring (); }     PublicIterator<item>iterator () {return NewListiterator<item>(first); }    Private classListiterator<item>ImplementsIterator<item> {        PrivateNode<item>Current ;  PublicListiterator (node<item>First ) { Current=First ; }         Public BooleanHasnext () {returnCurrent! =NULL; }  Public voidRemove () {Throw Newunsupportedoperationexception ();}  PublicItem Next () {if(!hasnext ())Throw Newnosuchelementexception (); Item Item=Current.item; Current=Current.next; returnitem; }    }         Public Static voidMain (string[] args) {Queue<String> q =NewQueue<string>(); Scanner in=NewScanner (system.in);  while(In.hasnext ()) {String Item=In.next (); if(!item.equals ("-") ) Q.enqueue (item); Else if(!Q.isempty ())            System.out.println (Q.dequeue ()); System.out.println ("(" + q.size () + "left on queue)"); }    }}

Java implementation of the queue class