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ArrayList not instantiating when Applet loads

Chad Clites
Ranch Hand

Joined: Aug 16, 2005
Posts: 134
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?
Ulf Dittmer
Marshal

Joined: Mar 22, 2005
Posts: 42264
    
  64
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?


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Chad Clites
Ranch Hand

Joined: Aug 16, 2005
Posts: 134
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.
 
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