The Java.util.Stack.removeAll(Collection col) method is used to remove all the elements from the Stack, present in the collection specified.
Syntax:
Stack.removeAll(Collection col)
Parameters: This method accepts a mandatory parameter col which is the collection whose elements are to be removed from the Stack.
Return Value: This method returns true if the Stack is altered due to the operation at all, else False.
Exception: The method throws NullPointerException if the specified collection is null.
Below programs illustrate the Java.util.Stack.removeAll(Collection col) method:
Program 1:
// Java code to illustrate removeAll()import java.util.*;  public class StackDemo {    public static void main(String args[])    {          // Creating an empty Stack        Stack<String> stack = new Stack<String>();          // Use add() method to add elements in the Stack        stack.add("Geeks");        stack.add("for");        stack.add("Geeks");        stack.add("10");        stack.add("20");          // Output the Stack        System.out.println("Stack: " + stack);          // Creating an empty Stack        Stack<String> colstack = new Stack<String>();          // Use add() method to add elements in the Stack        colstack.add("Geeks");        colstack.add("for");        colstack.add("Geeks");          // Remove the head using remove()        boolean changed = stack.removeAll(colstack);          // Print the result        if (changed)            System.out.println("Collection removed");        else            System.out.println("Collection not removed");          // Print the final Stack        System.out.println("Final Stack: " + stack);    }} |
Output:
Stack: [Geeks, for, Geeks, 10, 20] Collection removed Final Stack: [10, 20]
Program 2:
// Java code to illustrate removeAll()import java.util.*;  public class StackDemo {    public static void main(String args[])    {          // Creating an empty Stack        Stack<Integer> stack = new Stack<Integer>();          // Use add() method to add elements in the Stack        stack.add(1);        stack.add(2);        stack.add(3);        stack.add(10);        stack.add(20);          // Output the Stack        System.out.println("Stack: " + stack);          // Creating an empty Stack        Stack<Integer> colstack = new Stack<Integer>();          // Use add() method to add elements in the Stack        colstack.add(30);        colstack.add(40);        colstack.add(50);          // Remove the head using remove()        boolean changed = stack.removeAll(colstack);          // Print the result        if (changed)            System.out.println("Collection removed");        else            System.out.println("Collection not removed");          // Print the final Stack        System.out.println("Final Stack: " + stack);    }} |
Output:
Stack: [1, 2, 3, 10, 20] Collection not removed Final Stack: [1, 2, 3, 10, 20]
