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WHAT IS AN OBJECT AND A CLASS?

As we have discussed above, an Object-Oriented Programming language uses objects and classes. Let
us discuss them in detail.

Object

An object can be defined as a real-world entity such as a telephone, mouse or bag. All real-world
entities have properties and behaviours. Properties represent the physical appearance and qualities
of an object. On the other hand, behaviour represents the functions that an object can perform.
For example, a computer has a brand name, type and price as its properties. It also has "calculation" as
one of its behaviours.

Class

A class can be defined as a user-defined blueprint or prototype that is used to create objects. It
contains objects that have similar properties and behaviour. For example, an animal class has
different types of animals.

Animal

Cat Tiger Dog

All the animals in the animal class have similar behaviours such as eating, drinking and they also have
similar properties, such as colour, size and number of legs.

In the same way, a class in Java contains different types of objects that have similar properties and
behaviour. After declaring a class, we can create many number of objects from it.

NEED FOR METHODS

There is no use of a class without methods. Methods Definition
are necessary to perform operations on the data
members of a class. These are very useful as they Definition: A method in Java is a group of
reduce the size of a program. They occupy less space statements which can be used together
in memory and the execution becomes faster. They to perform a specific operation. These
increase the reusability of code. They reduce the can be used repeatedly, thus reducing
burden of debugging of programming code, so finding the length of code.
and correcting the errors becomes easy for the
developers.

FORMS OF METHODS

There are two forms of methods: predefined methods and user-defined methods. Let us study them
in detail.

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