JAVA CLASS OBJECTS AND METHODS

Java Classes , Objects and Methods
Objects : Class that defines the states and behavior of the basic program components known as objects.
Classes create objects and objects use methods to communicate between them
The data items are called fields and the functions are called methods. . calling a specific methods in a n objects is described as ending the objects a message.
Java program that incorporates the basic OOP concepts such as encapsulation, inheritance and polymorphism.
How to define a class
Class abc [extends superclass]
{
Variable name
Methods declaration
}

Adding variables :
Class rect {
Int length;
Int breadth;
Int length, breadth;
}
Adding methods:
Type method name (parameter-list)
{
Method type
}

Creating objects :
Rect rect1; / /declare
Rect1 = new ract(); // instance

How to access class member
Rect1.methodname(parameterlist);

Constructors : same name as the class itself. They return the instance of the class itself.

Methods overloading :it is possible to create methods that have the same name , but different parameter and different definitions. This is called a method overloading.
Why we need method overloading: objects are required to perform similar tasks but using different input parameters. So when we call a methods in a objects. This process called is a polymorphism.
Class room
{float l, w;}
Room(float x, float y) // constructor1
{ l=x;
W=y;
}
// constructor 2
Room (float x)
{ l=w=x;
}
Int area()
{
Return (l *w);
}
}
Methods define :
Return type
Name of the method
A list of parameters
Body of the method

Class methods:
Used only with respect to the instance of the class. An object has to be created in order to use the instance method. Class method do not requires an instance of the class for using.
Int val = Integer.parseInt(“50”);
Command line argument : run with given argument at the command line.
Command line argument : run with given argument at the command line.