Stack empty() Method in Java

The java.util.Stack.empty() method is used to check whether a stack contains any elements. It returns a boolean value—true if the stack is empty, and false otherwise. This method is commonly used to avoid EmptyStackException, control stack traversal, and implement safe error handling.

Syntax:

stack.empty()

Parameters: The method does not take any parameters.
Return Value: The method returns true if the stack is empty, else it returns false.

Example 1: Checking Stack Emptiness Before and After Pop

Java

import java.util.Stack;

public class StackDemo {
    public static void main(String[] args) {

        Stack<String> stack = new Stack<>();

        stack.push("Geeks");
        stack.push("4");
        stack.push("Geeks");
        stack.push("Welcomes");
        stack.push("You");

        System.out.println("Stack: " + stack);
        System.out.println("Is stack empty? " + stack.empty());

        while (!stack.empty()) {
            stack.pop();
        }

        System.out.println("Is stack empty? " + stack.empty());
    }
}

Output

Stack: [Geeks, 4, Geeks, Welcomes, You]
Is stack empty? false
Is stack empty? true

Example 2: Checking Emptiness of an Integer Stack

Java

import java.util.Stack;

public class StackDemo {
    public static void main(String[] args) {

        Stack<Integer> stack = new Stack<>();

        stack.push(8);
        stack.push(5);
        stack.push(9);
        stack.push(2);
        stack.push(4);

        System.out.println("Stack: " + stack);
        System.out.println("Is stack empty? " + stack.empty());
    }
}

Output

Stack: [8, 5, 9, 2, 4]
Is stack empty? false

Example 3: Traversing a Stack Using empty() (Sum of Elements)

Java

import java.util.Stack;

public class StackDemo {
    public static void main(String[] args) {

        Stack<Integer> stack = new Stack<>();

        stack.push(23);
        stack.push(3);
        stack.push(-30);
        stack.push(13);
        stack.push(45);

        System.out.println("Stack: " + stack);

        int sum = 0;

        while (!stack.empty()) {
            sum += stack.pop();
        }
        System.out.println("Sum of elements: " + sum);
        System.out.println("Is stack empty? " + stack.empty());
    }
}

Output

Stack: [23, 3, -30, 13, 45]
Sum of elements: 54
Is stack empty? true

Example 4: Using empty() for Error Handling

The empty() method is useful for validating input scenarios, such as checking whether a file contains data before processing.

Java

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
import java.util.Stack;

public class FileReadExample {

    public static void main(String[] args) {

        Stack<String> stack = new Stack<>();

        try {
            File file = new File("data.txt");
            Scanner scanner = new Scanner(file);

            while (scanner.hasNextLine()) {
                stack.push(scanner.nextLine());
            }
            scanner.close();

        } catch (FileNotFoundException e) {
            System.out.println("File not found.");
        }

        if (stack.empty()) {
            System.out.println("File is empty.");
        } else {
            System.out.println("File is not empty. Stack contents:");
            while (!stack.empty()) {
                System.out.println(stack.pop());
            }
        }
    }
}

Output

File not found.
File is empty.

Stack empty() Method in Java

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