Stack Implementation in JAVA

import java.util.ArrayList;

/**
 *  Write a Java program to implement Stack in Java
 */
public class StackImplementation {
   private ArrayList<Object> container = new ArrayList<>();
   private static int counter = -1;

    /**
     * Pushes items into the stack
     * @param object is the pushable object
     */
   public void push(Object object){
       container.add(object);
       counter++;
   }

    /**
     * Pops the last item from the stack
     * @return the last item from the stack
     */
    public Object pop(){
       if (!container.isEmpty()) {
           Object temp = container.get(counter);
           container.remove(counter);
           counter--;
           return temp;
       }
        return null;
    }

    /**
     * Checks if the stack is empty or not
     * @return true if the stack is empty, false if not
     */
    public boolean isEmpty(){
        return counter == -1;
    }

}