Question

So my problem is this. I have a class called Globals that contains all the variables I need all over the program. It works fine for things like strings, integers and other things that you can use the = operation on. For example:

public class Globals {
   public static int globalInteger = 23;
   public static String globalString = "Hello, dude.";
   public static UserProfile globalUserProfile;
}

Somewhere in the project, I access them using these:

Globals.globalInteger += 17;

Globals.globalString = "Why, hello there!";

However, I am trying to make a class that I wrote myself global (UserProfiles.class). This class does not use the = operation, hence, it is always null when I access it from somewhere else and I get java.lang.nullPointerException. For example if I do this (newProfile(String) is a method inside UserProfiles.class):

Globals.globalUserProfile.newProfile(profileName);

I get java.lang.NullPointerException. How can I make my UserProfile.class variable accessible all throughout the project? Thanks in advance.

Answer 1

Try Singleton design pattern.

http://en.wikipedia.org/wiki/Singleton_pattern

Examples of GoF Design Patterns in Java's core libraries