Comments 2
But why not give them proper descriptive names when there's more than a couple of type parameters and their meaning is not completely obvious? The type parameter names never appear on the type's use sites, so giving them longer names does not put any burden on the users.
It is up to you, if you like can give long names.
but from my perspective by capital letters better:
Closer to convention. It states that should be one letter + digits. Here I suggest by capitals. For example if class name contain 3 words - will be 3 letters. It exactly defines the class is such case.
Class name could be really long - how will you name type parameter in this case? It will match to class name? Long parameter names - not usual practice.
Class name could differ only by 1 word from 3. For example - FlowParamBuilder and TaskParamBuilder. How you suggest to name type parameter in this case? I think that FPB and TPB will fit good here. If needed - even in IDEA you can find the class by type parameter capitals.
Apply «capital letters jam» for generic type parameters