What is the Stack.containsAll method in Java?

The Stack class is a Last-In-First-Out (LIFO)The element inserted first is processed last and the element inserted last is processed first. stack of objects.

The containsAll() method checks if all of the elements of the specific collection object are present in the Stack object.

Syntax

public boolean containsAll(Collection<?> c)

Argument

The collection to be checked for in the Stack is passed as an argument.

Return Value

containsAll() returns true if all of the elements of the passed collection are present in the Stack.

Code

import java.util.Stack;
import java.util.ArrayList;
class containsAll {
public static void main( String args[] ) {
Stack<Integer> stack = new Stack<>();
stack.add(1);
stack.add(2);
stack.add(3);
ArrayList<Integer> list1 = new ArrayList<>();
list1.add(1);
list1.add(3);
System.out.println("The stack is "+ stack);
System.out.println("\nlist1 is "+ list1);
System.out.println("If stack contains all elements of list1 : "+ stack.containsAll(list1));
ArrayList<Integer> list2 = new ArrayList<>();
list2.add(4);
System.out.println("\nlist2 is "+ list2);
System.out.println("If stack contains all elements of list2 : "+ stack.containsAll(list2));
}
}

Explanation

In the code above:

  • In lines 1 and 2: We import the Stack and ArrayList classes.

  • In line 4: We create an object for the Stack class with the name stack.

  • In lines 6 to 8: We add three elements (1,2,3) to the created stack object.

  • In line 10: We create a new ArrayList object with the name list1 and add the elements 1,3 to it.

  • In line 16: We call the containsAll() method to check if all elements of list1 are present in the stack. In this case, the method returns true because all the elements of list1 (1,3) are present in the stack.

  • In line 18: We create a new ArrayList object with the name list2 and add the element 4 to it.

  • In line 22: We call the conainsAll() method again to check if all elements of list2 are present in the stack. In this case, the method returns false because element 4 of list2 is not present in the stack.