cast from IFeatureClass to ISchemaLock (ARCGIS)

Hi

I'm programming with the ARCGIS Java SDK, in Eclipse.

I need to cast an IFeatureClass to an ISchemalock. This cast is supposed to be allowed. There is an example of this cast in: http://resources.esri.com/help/9.3/a...35f906bb2e.htm

However, when I try to perform this cast in my code, an exception appears:

Exception in thread "main" java.lang.ClassCastException: com.esri.arcgis.geodatabase.IFeatureClassProxy cannot be cast to com.esri.arcgis.geodatabase.ISchemaLock

Are you able to make this cast on an IFeatureClass ? Here is the code to perform this:
I would appreciate if you could try this simple line of code in one of your programs, and let me know if you get an exception.

Keep me posted...