How can I use my array in another method.... Or better yet, what's wrong?

Question

I guess I'll show you what I am trying to do rather and then explain it
public class arraycalc
int[] dog;
public void arraycalc()
dog = new int[2];
public void setSize(int size)
dog[1] = size;
public int getSize()
return dog[1];
This gives me a null pointer exception...
How can I use my array from other methods?

Answer 1

You have to make the array static. :)
Although I must admit, this is rather bad usage. What you want to do is use an object constructor to make this class an object type, and then create the array in your main class using this type, and then call the methods from this class to modify your array. Creating the array inside the other method leads to a whole bunch of other stuff that's ... well, bad. :)
Another thing: Because you're creating your array inside this class and you want to call your array from another class, you need to make the array static; to make it static, you must make your methods static. And according to my most ingenious computer science teacher, STATIC METHODS SUCK. :D
So, if you want to stick with your layout, it would look like:
public class arraycalc
     static int[] dog;
     public static void arraycalc()
          dog = new int[2];
     public static void setSize(int size)
          dog[1] = size;
     public static int getSize()
          return dog[1];
}But I must warn you, that is absolutely horrible code, and you shouldn't use it. In fact, I don't even know why I posted it.
You should definitely read up on OOP, as this problem would be better solved by creating a new object type.