Q4018 Why do I keep getting a "java.lang.NullPointerException" when using arrays?

    // example of an incorrectly initialized array:

       public class Test {
          public static void main(String args[]) {
             String sa[] = new String[5];
 
             sa[0].charAt(0);
          }
       }


    // example of a correctly initialized array:

       public class Test {
          public static void main(String args[]) {
             String sa[] = new String[5];

             for(int i = 0; i < 5; i++) {
                sa[i] = new String();
             }
 
             sa[0].charAt(0);
          }
       }