Classes and Objects

In java, all data and functions are declared in a class. To declare a class, keyword class is used. Keyword class is followed by class name. Class is a collection of objects that contains a set of data items (Properties) and related functions (Behaviours). Class is a way to bind the data describing an entity and its associated functions together. Class contains Instant variables, Constructors, and Member methods. Instance variables are generally used within the member methods of the class. The variables that are declared within class are called Instance variables. Each object of a class contains these variables. These are used in the member function.

A constructor in a class is a special type of method called at the creation of an object. It is called a constructor because it constructs the values of data members of the class. They have same name as a class without any access modifier. Member methods deal with instant variables. Member methods are the methods inside the class. These methods deal with instance variables. Member methods are common to all the objects. Objects are created using the new operator along with the class constructor. It allocates memory and returns the reference to the newly created object. An object is an instance of a class which is used to invoke class elements such as methods.  Through objects’ interaction, a program can carry out various tasks. Once a class is declared, its variable is created, which is known as an object.

To Access the full content, Please Purchase

  • Q1

    What is the other name given to composite datatype?

    Marks:1
    Answer:

    User-defined datatype.

    View Answer
  • Q2

    Define composite datatype?

    Marks:1
    Answer:

    A composite datatype is any datatype which can be constructed in a program using primitive datatypes of its programming language.

    View Answer
  • Q3

    Give examples of primitive datatype?

    Marks:1
    Answer:

    Java provides eight primitive datatypes. They are byte, short, int, long, float, double, char and boolean.

    View Answer
  • Q4

    Define primitive datatype.

    Marks:1
    Answer:

    A primitive datatype is predefined by the language and is named by a reserved keyword. Primitive values do not share state with other primitive values.

    View Answer
  • Q5

    What do you understand by the term datatype?

    Marks:1
    Answer:

    A datatype in a programming language is a set of data with values having predefined characteristics.

    View Answer