Erroneous usage of assert keyword

Using assert keyword in productive code is not the correct way.

E.g. QPartitionOperations.java.findQPartition() uses assert to check that this method is called with at least 2 diagnoses. This is wrong! Throw an exception instead.

Also, findQPartitionRek() is using assert sucs.remove(p1) which is omitted by the compiler if no -ea flag is set. This does results in a major misbehaviour where this relevant code snipped is not executed because of compiler omission.