Xenon

First off Ill say this is a Uni Assignment, ive pretty much finished the assignment, only I keep getting Null Pointer Exceptions and its driving me crazy, the reason I say I need urgent help is that the assignment is due in in 10 hours, we were give 2 weeks to do it and I wont let all this work go to waste because of a stupid null pointer.

The assignment is basically to make a media management system for Photos, Sound Bites and Video Clips.

The media classes are all inherited from one class called MediaItem, there is a CatalogueArray (note: CatalogueArray NOT Catalogue) class which has all the add and delete functions, and also main class called MediaGui, there are also some other classes that arent used for anyhting yet.

Basically as youll se fom running the program, when you try to "Save" a media item, after filling in all the correct details, you will get a null pointer error, you will also get one when you load a library in and a few other things, I am having a huge time trying to sort this out and just cant do it, im hoping that a fresh set of eyes will spot it straight away.

I dont hold many high hopes for getting this done in time as it is very short notice, but if anyone can help me id be so unbelievably greatful.

I exported my whole project from eclipse into a file system and have uploaded it to my web space - http://www.dark-designs.co.uk/downlo...mentSystem.zip

2roll4life7

I can't get it to compile on this computer I'm at but NullPointerExceptions occur when you declare an object but don't initialize it, then try to use that object. If you post the actual exception (and the line number that's given, I could be of more help).

__________________
- libpng version 1.2.8 (example.c)

<Jim_McNeat> Is there like a way to put a compiler in "Just trust me on that one" mode?

xavier

Maybe i'm just not seeing it, but in your CatalogueArray do you ever initialize numberOfMediaItems. Cause you keep comparing it but i can't see where you initialize it. Also the private MediaItem [ ] mediaItems;.

I'm probably waaay off

__________________
Don't take life too seriously, it's not permanent !

Xenon

OK initialising numberOfMediaItems to 0 seems to of fixed some things, now when I load a library file in I ge this Null Pointer:

java.lang.NullPointerException
at mediaManagementSystem.CatalogueArray.displayAll(CatalogueArray.java:433)
at mediaManagementSystem.MediaGui$18.actionPerformed(MediaGui.java:556)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$ForwardActionEvents.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.AbstractButton.doClick(Unknown Source)
at javax.swing.plaf.basic.BasicMenuItemUI.doClick(Unknown Source)
at javax.swing.plaf.basic.BasicMenuItemUI$MouseInputHandler.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)

xavier

initialize mediaItems also ... cause you work with it all the time , but i can't see where u're initializing it

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Don't take life too seriously, it's not permanent !

2roll4life7

You have an array of MediaItem objects that you have to make sure everyone is initialized before you can use the objects in your displayAll() function. I don't have time to check all your code for this right now, but I'm fairly confident that is your problem here.

__________________
- libpng version 1.2.8 (example.c)

<Jim_McNeat> Is there like a way to put a compiler in "Just trust me on that one" mode?

Xenon

Sorry, im not that great with Java as you may have noticed, how to I check everything is initialized

xavier

I think by hand ... Also i have a question :

will it ever return "The Media library is empty";

__________________
Don't take life too seriously, it's not permanent !

2roll4life7

As Xavier said, in your private array mediaItems. Have a for loop run through the entire array and at each position set the object there to whatever it should be.

__________________
- libpng version 1.2.8 (example.c)

<Jim_McNeat> Is there like a way to put a compiler in "Just trust me on that one" mode?

Xenon

Oh yea the "numberOfMediaItems = 10;" was me testing stuff, ive removed it now.


Sorry, I know this is really cheeky only im desperate as have absolutely no time, could you give me some code for the for loop, i know thats really cheeky.