By convention, type parameter names are single, uppercase letters. This stands in sharp contrast to the variable naming conventions that you already know about, and with good reason: Without this convention, it would be difficult to tell the difference between a type variable and an ordinary class or interface name.
The most commonly used type parameter names are:
- E – Element (used extensively by the Java Collections Framework)
- K – Key
- N – Number
- T – Type
- V – Value
- S,U,V etc. – 2nd, 3rd, 4th types
You’ll see these names used throughout the Java SE API and the rest of this lesson.