I'm just starting on a project where I want to make a display object that constructs and array of pixel objects when it is created. I thought I had the concepts down but I get a "java.lang.NullPointerException". If anyone has run into something similar and knows the proper procedure could you let me know?

Thanks,

Chris

My Code (I've simplified it down to the offending structure)

2. Display myDisplay = new Display();
3. 
   
4. class Display {
5.   
6.   Pixel[] pixelArray;
7.   
8.   Display() {
9.     build();
10.   }
11.   
12.   void build() {
13.     for ( int i = 0; i < 4; i++ ) {
14.       pixelArray[i] = new Pixel();
15.     }
16.   }
17.   
18. }
19. 
    
20. class Pixel {
21.   
22.   Pixel() {
23.     
24.   }
25.   
26. }

My Error

2. Exception in thread "main" java.lang.RuntimeException: java.lang.NullPointerException
3. at processing.core.PApplet.main(PApplet.java:7254)
4. Caused by: java.lang.NullPointerException
5. at sketch_aug15a$Display.build(sketch_aug15a.java:32)
6. at sketch_aug15a$Display.<init>(sketch_aug15a.java:27)
7. at sketch_aug15a.<init>(sketch_aug15a.java:20)
8. at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
9. at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
10. at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
11. at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
12. at java.lang.Class.newInstance0(Class.java:355)
13. at java.lang.Class.newInstance(Class.java:308)
14. at processing.core.PApplet.main(PApplet.java:7252)
15.