What is reference type data type?

Definition:
The reference type data type is used to refer to an object of any class.
The reference type data type are also called as user-defined data type or derived data type.

Example:
Class, Array, Interface etc.

Discussion:
A class is also called as user-defined data type because the structure of the class is defined by the user according to the requirement of the program.
A class is also called as derived data type because the structure of the class is derived from the primitive data type.

Size and range:

Syntax:
Class Student
{
    int roll;
    String name;
    float marks;
}

Program:

Video: