How to use ArrayList?

Question

i'm not quite sure how to use ArrayList, i read the api documentation but it would be better if someone could explain it to me
i have a helper method that returns a random number within a given range that picks an index at random but it won't work, here is my code:
     public String getIndex ()
          a1.get(getRandomIndex(int));
     private static int getRandomIndex (int range)
          return ((int) (Math.random () * range));
     }

Answer 1

You are calling he method incorrectly. You do not use the variable type declaration when calling a method. Do this
import java.util.*;
public class TestClass{
     ArrayList<String> words = new ArrayList<String>();
     Random rand = new Random();
     public TestClass(){
          words.add("hello");
          words.add("world");
     public String randomSelection(){
          int index = rand.nextInt(words.size());
          return words.get(index); //notice that I am calling the method with a variable that is an integer, but I don't use "int" when I call it
     public static void main(String args[]) {
          TestClass myTest = new TestClass();
          for(int i=0;i<30;i++){
               System.out.println(myTest.randomSelection());
}The API documentation will list the variable type but that is only for you information. It is there so that you know what type of variable top use when calling a particular method.