Simple java class program example

Python Pillow. Python Turtle. Verbal Ability. Interview Questions. Company Questions. Artificial Intelligence. Cloud Computing. Data Science. Angular 7. Machine Learning. Data Structures. Operating System. Computer Network. Compiler Design. A class can implement more than one interface. Constructors are used for initializing new objects. Fields are variables that provides the state of the class and its objects, and methods are used to implement the behavior of the class and its objects.

There are various types of classes that are used in real time applications such as nested classes , anonymous classes , lambda expressions. Object It is a basic unit of Object-Oriented Programming and represents the real life entities. A typical Java program creates many objects, which as you know, interact by invoking methods. An object consists of : State : It is represented by attributes of an object. It also reflects the properties of an object.

Behavior : It is represented by methods of an object. It also reflects the response of an object with other objects. Identity : It gives a unique name to an object and enables one object to interact with other objects. Example of an object: dog. Skip to content. Change Language. Related Articles. Basics of Java. Operators in Java. Packages in Java. Flow Control in Java. Before we create an object, we first need to define the class.

We can think of the class as a sketch prototype of a house. It contains all the details about the floors, doors, windows, etc. Based on these descriptions we build the house. House is the object.

Since many houses can be made from the same description, we can create many objects from a class. Here, fields variables and methods represent the state and behavior of the object respectively. In the above example, we have created a class named Bicycle. It contains a field named gear and a method named braking. Here, Bicycle is a prototype. Now, we can create any number of bicycles using the prototype.

And, all the bicycles will share the fields and methods of the prototype. Note : We have used keywords private and public. These are known as access modifiers. To learn more, visit Java access modifiers.

An object is called an instance of a class. For example, suppose Bicycle is a class then MountainBicycle , SportsBicycle , TouringBicycle , etc can be considered as objects of the class.

We have used the new keyword along with the constructor of the class to create an object. Constructors are similar to methods and have the same name as the class.

For example, Bicycle is the constructor of the Bicycle class. To learn more, visit Java Constructors. Here, sportsBicycle and touringBicycle are the names of objects. We can use them to access fields and methods of the class. As you can see, we have created two objects of the class. We can create multiple objects of a single class in Java. Note : Fields and methods of a class are also called members of the class. We can use the name of objects along with the.