Replace Type Checking with Strategy Pattern

GMTInfoKeeper.java class contain a method called removeRegistration with
a nested conditional statement shown in code smell 2, that involves type
checking. Refactoring pattern applied was strategy pattern by creating a
new method called getPoIdentitty (method of type POidentity – and
interface to different algorithm), whose responsibility involves
switching between algorithm depending on the parameter, and proper
reference is made to this method