java.util.Stack

java.util.Stack is a last-in, first-out (LIFO) data structure that extends the Vector class and is part of the Java Collections Framework. It models the classic stack data structure where elements are added and removed only from the top of the stack. Internally, since Stack extends Vector, it inherits all of its methods and characteristics, including synchronization, meaning all operations on a Stack object are thread-safe. The Stack class introduces several methods specifically designed for stack operations, such as push(E item) to insert an element at the top, pop() to remove and return the top element, peek() to look at the top element without removing it, and empty() to check if the stack is empty. Because it is synchronized,

Stack is safe for use in multi-threaded environments but might be less efficient in single-threaded applications. In modern Java programming, Deque (such as ArrayDeque) is often preferred over Stack due to its improved performance and flexibility, but Stack is still useful for educational purposes and simpler use cases requiring built-in synchronization.