The model used to open the store is incompatible with the one used to create the store

Killed the main thread

Root View: the pane on the left when iPad is in Landscape mode Detail View: the main pane of display

It turns out I was trying to send release message to a NSArray instance which was created using the class method arrayWithObjects:

It is probably a wrong conclusion, but commenting out the line works.

Is it the equivalent of segfault in unix or NPE in java?

Anyway, having fun with it…

Basically, there is no support of Abstract base class in objective-c.

The handling is similar to what you can do in python (pre-2.6): inside the supposedly abstract class method throws an exception.