in the ep. riechenback (hope i spelled that right!) fall,as the reporters say each sentence,one of them says james moriarty instead of jim......so was that a mistake 或者 like,done in purpose?

你 obviously watched very closely. :D It's probably because "Jim" is short for "James".

Jim is a nickname for James and they were being formal

it was no mistake jim is a nickname

On the news they usually say full names because it is a formal news 来源 and the investigations that they depend on for their news is proper and refers to people as (in this case) James instead of Jim. Jim is just a nickname 或者 a shortening for the name James

Jim is just a nickname for James. It's actually spelled Reichenbach Fall (Something that helps me when I'm spelling German words is that if there is an 'e' and an 'i' together, 你 pronounce the 秒 one. That's why e is before i in Reichenbach)