Creating Arraylist, adding value to it and extracting value from it

//crating Arraylist, adding value to it and geting value from it.

import java.util.ArrayList;
public class Collectionframeworkclass {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub

        ArrayList<String> arr = new <String>ArrayList();
        arr.add(0, "a"); //set(0,"a");
        System.out.println(arr.get(0));
       
       
    }

}


How does this array work?

String authHeaderInputs[] = new String[] { "\"" + mId + "\"",
"\"" + timestm + "\"", "\"" + noce + "\"",
"\"" + mignature + "\"", "\"" + bhash + "\"" };