Java: Long (class) vs long (primitive)
Long is a class, or a reference type, defined in the standard library. It stores a reference to an object containing a value (a "box").
long on the other hand, is a primitive type and part of the language itself. It stores an actual value.
We say that
Long is the wrapper type for
long, and objects of type
Long are boxed values.
Continue reading here:
Java: Primitives vs Objects and References
Java: Wrapper Types