This is not a problem so much as an observation that I don't understand. I am working with a JApplet in Netbeans, and I have an Arraylist as a Global variable, and I created it simply by using ArrayList aa;. I have a loop that loads the ArrayList, and I kept getting a null pointer error. Once I changed the ArrayList constructor to ArrayList aa= new ArrayList();, the null pointer error goes away.
I've been looking through the docs, and I can't find why this is. I thought all objects declared globally just used a default constructor? Is it different for applets?
I thought all objects declared globally just used a default constructor?
No, object are not instantiated automatically, and will always be null. Only primitives get assigned a default value. What piece of code gave you the idea that objects were instantiated automatically?
Joined: Aug 16, 2005
I don't have one good reason to think that, actually. I also can't think of any time I was presented with the fact that objects were null. Probably a by-product of too many hours in an IDE and not enough in a text editor, not that it is any excuse.
subject: ArrayList not instantiating when Applet loads