0 How to Invoke methods in a Java class?

Invoking methods in a class

The following statement creates a new "Student" object and assigns its reference to "student".

Student student = new Student();

All the public members of the object can be accessed with the help of the reference.

Student student = new Student();
student.setRollNo(20);
System.out.println(student.getRollNo());

 The reference can be treated as the name of an object.
For using a Student object, a programmer need not know the internal implementation details of the class. One needs to know only the public methods to use a Student object. Abstraction is achieved by hiding the irrelevant implementation details and exposing the relevant interface details.