Program java vectors

import java.util.Vector; //Needed for the Vector itself.
import java.util.Scanner; //Needed for console input.

class Main extends Thread { //The extension/inheritance is only for the 3.5 second waits I've placed, not required for Vectors.
    public static void main(String[] args) throws InterruptedException { //The throw is only for the 3.5 second waits I've placed, not required for Vectors.
        int i=0, index=-1;
        Integer element;
        Integer[] exampleArray = new Integer[25];
       
        //Info.
        System.out.println("**This shows you a bit about the Vector class as an alternative to arrays.**\n");
        Thread.sleep(3500); //These just has the app wait for 3.5 seconds to let you catch up.
       
        /* Declare the Vector.
         * NOTE: Primitives cannot be used; use autoboxing/autounboxing & wrappers instead (like Integer, below)
         */
        Vector<Integer> exampleVector = new Vector<Integer>();
       
        //We haven't initialized the Vector yet, so it's empty. See for yourself:
        if(exampleVector.isEmpty()) System.out.println("Yup, it's empty alright.\n");
        Thread.sleep(3500);
       
        //Now we'll add to the Vector. Let's get it done quickly by using a for loop to add 10 items:
        System.out.print("Here are the elements we're adding: \n");
        for(i=0; i<10; i++) {
            exampleVector.addElement(i);
            System.out.print(i + " ");
        }
        System.out.println("\n");
        Thread.sleep(3500);
       
        /* But wait! I want to add 100 to the 4th position (index 3). If this were an array, we'd be running into a few problems here,
         * but since this is a Vector, it's as easy as: */
        exampleVector.insertElementAt(100, 3);
        //Now, check it out (also notice the for condition's operator ( .size() ):
        for (i=0; i<exampleVector.size(); i++) {
            System.out.print(exampleVector.elementAt(i) + " "); //Also notice how we get at elements: the elementAt(index) dot-operator.
        }
        System.out.println("\n");
        Thread.sleep(3500);
       
        //We can check if the Vector contains a specific element anywhere by using the .contains(Object) method:
        System.out.println("Is the number 2 in the Vector?");
        if(exampleVector.contains(2) == true) System.out.println("--> Yup.\n");
        else System.out.println("--> Nope.\n");
        Thread.sleep(3500);
       
        //Ok. So now we know an element is present. What if I want to know its index so I can change it? It's this easy:
        index = exampleVector.indexOf(2);
        System.out.println("2 is at the index " + index + "\n");
        Thread.sleep(3500);
       
        /* Actually, I've decided that I don't want 2 in the list anymore. I want to delete it.
         * Again, if this were an array, this would present some problems, but with a Vector, all we do is: */
        exampleVector.removeElement(2);
        //We also could have used the following code: exampleVector.removeElementAt(exampleVector.indexof(2)); -- they're equivalent.
        //Let's see what happened:
        for (i=0; i<exampleVector.size(); i++) {
            System.out.print(exampleVector.elementAt(i) + " ");
        }
        System.out.println("\n");
        Thread.sleep(3500);
        //**The really cool thing about Vectors is that their actual size is dynamic. That element we removed
        //  actually shortened the whole Vector. Arrays are fixed in size once they are declared - inconvenient, huh?
       
        //Of course, there are tons of other Vector methods; I suggest you head over to the API & check them out. Here are a couple:
        //firstElement:
        System.out.println("What's the first element in the Vector?");
        element = exampleVector.firstElement();
        System.out.println("--> " + element);
        //lastElement:
        element = exampleVector.lastElement();
        System.out.println("What's the last element?\n--> " + element + "\n");
        Thread.sleep(3500);
       
        //If, for some weird reason, you really need an array, you can copy your Vector into an array like this:
        exampleVector.copyInto(exampleArray);
        //Let's see if it's really there:
        for(i=0; i< 25; i++) {      //25 is the length of the array above.
            if(exampleArray[i] != null) System.out.print(exampleArray[i] + " ");
        }
        System.out.println("\n");
        Thread.sleep(3500);
       
        //Lastly, we can clear the Vector to end with what we started with like this:
        exampleVector.removeAllElements();
        System.out.println("Empty?");
        if(exampleVector.isEmpty() == true) System.out.println("Yup, it is.\n");
        else System.out.println("Nope. \n");
        Thread.sleep(3500);
       
        System.out.println("Well, that's the end of this tutorial/snippet. Hope you learned a bit about the advantages of using Vecotrs." +
                            "\nIf you're interested in learning more, you should check out the API to unlock all the Vector class' possibilities in your apps.!");
       
    }
}