[An extra null pointer check is not needed in functions](https://isocpp.org/wiki/faq/freestore-mgmt#delete-handles-null "Do I need to check for null before delete p?") like the following. - [ISingleton::releaseInstance](https://github.com/famez/J1939-Framework/blob/3b8456697d7795cafcb39a60379fdc6f90a57c47/Common/include/Singleton.h#L72 "ISingleton::releaseInstance function") - [J1939Factory::unregisterAllFrames](https://github.com/famez/J1939-Framework/blob/3b8456697d7795cafcb39a60379fdc6f90a57c47/J1939/J1939Factory.cpp#L37 "J1939Factory::unregisterAllFrames function")
