About Question enthuware.oce-jpad.v6.2.455 :

[PtFyEH]

As per section 3.2.7.1 it is not guaranteed that an IllegalArgumentException will be thrown in Line 4. Execution might also just continue and result in a transaction rollback when a commit is attempted (and print "false" (i.e. option 2) before that as per seciton 3.2.8):

If X is a removed entity instance, an IllegalArgumentException will be thrown by the
merge operation (or the transaction commit will fail).

[admin]

You are right. Fixed.
thank you for your feedback!
Paul.