Runtime EXception on re-compile the code in Blackberry

I've created app.It working fine.

When i've changed some code and compile, it throws "Runtime EXception."

After i've deleted *.dmp file. Its working fine.

Everytime i compile it throw开发者_运维技巧 the exception. i delete *.dmp file and re execute.

Pls help me what is the problem and how to avoid it.

On my experience this error is connected to changes in data structures you save/load from/to PersistentStore.

If you have stored object with a particular structure, and after that you change your object structure, you will get exception upon loading this object from the persistent store.

Removing dmp files cleans your simulator persistent store and your app works fine. But with old, non-compatible objects stored in dmp file (simulator persistent store) you get the exception.