How are character names chosen?

Are literary names always meaningful, or are some characters named quite casually? Does each genre have a list of first names available only for that sort of writing? Corydon, a stock-name for a shepherd, is obviously pastoral, whilst Hodge is clearly georgic. (Thomas Hardy wrote of the farm labourer ‘personified by the pitiable picture known as Hodge’.) Is it necessary for fictional characters to be named at all? After all, in romances a name can be withheld for much or all of the story. When it does emerge it may not be a full name. (Full names, complete with surname, have a history of their own and deserve a dedicated blog post in their own right.) Alastair Fowler su oupblog.