Java Run-Time problems

Question

I am new to Java and am trying to write a simple program.
The test class will instantiate an object of the "house" class which will in turn contain an array of 20 objects of the "player" class.
Compiles with no errors or warnings, but gives an immediate:
Exception in thread "main" java.lang.NullPointerException at test.main(test.java:6)
test.java
public class test
        private static house h;
        public static void main(String args[])
                h.players[3].setName("john");
}house.java
public class house
        public player[] players = new player[20];
}player.java
public class player
        private static String name;
        public static void setName(String n)
                name = n;
}What seems to be the problem? To my untrained eyes I can't find any errors.

Answer 1

alphacoder wrote:
Thanks for the help. It fixed my problem.Good to know.
How do I solve the 20 null references problem?That depends soley on what you want your class to do.
Do I just initialize all 20 references in the house constructor?If you want it to always reference 20 persons, then do so.
Alternatively you could track how many persons are currently in there and only add a new one when addPerson() is called (or something similar).
Also, you should avoid this kind of direct access to other classes member variables, it's against encapsulation (that's probably something you'll learn later in the course/book/tutorial, but I'd like to mention it).