I'm learning JDO through the use of Roos's wonderful free book, Eclipse, JPOX, and Oracle 10g database.
However I am facing a couple of pretty misterious mistakes. First of all, the execution of a client program (who uses enhanced objects either to simply create a new one or get an Extent) is horribly, horribly slow - even inserting one row to a one column table takes about a minute, or more.
But this is not the worst thing - once I started experimenting with Collections and subclasses, the execution started to take 5 minutes and then comes up this error:
What am I doing wrong? Can someone please tell me?