In this tutorial, you will learn the basic implementation of Stack with Java. You will also quickly walk through some official supports of Stack in Java such as java.util.Deque, java.util.concurrent.BlockingDeque and java.util.Stack

What is Stack Data Structure?

Stack is a linear data structure of similar data type items, stores data in LIFO (Last In First Out) order

Basic operations

  • push adds an item onto the stack
  • pop removes last pushed item from the stack
  • peek returns the last item pushed onto the stack

Other operations

  • isEmpty returns true if no more items can be popped
  • isFull returns true if no more items can be pushed
  • size returns the number of items on the stack

Implementation

You can implement a stack with either a linked list or an array (static or dynamic)

Stack implementation example with Static Array


Application

  • Depth First Search uses a stack to track which elements to visit next

Stack implementations in Java

  • java.util.Deque (interface), since Java 1.6, unsynchronized / not thread-safe, using in single threaded environment. For example
Deque<Integer> stack = new ArrayDeque<>();  
stack.push(1);  
stack.peek();  
stack.pop();  
  • java.util.concurrent.BlockingDeque (interface), since Java 1.6, synchronized / thread-safe, using in multi threaded environment. For example
BlockingDeque<Integer> stack = new LinkedBlockingDeque<>();  
stack.push(1);  
stack.peek();  
stack.pop();  
  • java.util.Stack (class), since Java 1.1, extends Vector, synchronized, should not be used due to its negative impact on performance