What is the difference between a, B, T, E, K, V in Java?

Using generics

list<t> list = new arraylist<t> ();

T t = list.get (0);

Do not use generics

List List = new ArrayList ();

T t = (t) list.get (0);

List is the same as list<?>.

Reference Document: http://825635381.iteye.com/blog/2017650

Object ... In ... The meaning

Public Long Remove (Object ... values) {
Return Ops.remove (GetKey (), values);
}

... Indicates that values is an array format, and if a list is passed, the format does not match, and the open source software does not handle the method internally

What is the difference between a, B, T, E, K, V in Java?