djo/dequeue.java

## dequeue.java
// Enhanced and fixed the dequeue method
if (first == null) return null;
Object item = first.data;
first = first.next;
if (first == null) last = null;
return item;

## description.md

      
    Raw
  

              description.md
            
          
    Book:
    Cracking Coding Interview 5th edition
  
  
    Chapter 3:
    Stacks and Queues
  
  
    Section:
    Implementing a Queue
  
  
    Page:
    80
  

The "last" reference should be nullified if a queue becomes empty in the "dequeue" method:
17: first = first.next;
++: if (first == null) last = null;
18: return item;

Otherwise "last" item will not be cleared by the GC on an empty stack.
	// Enhanced and fixed the dequeue method
	if (first == null) return null;
	Object item = first.data;
	first = first.next;
	if (first == null) last = null;
	return item;
Book:	Cracking Coding Interview 5th edition
Chapter 3:	Stacks and Queues
Section:	Implementing a Queue
Page:	80