The objects are data
and methods bundled together into a single logical software unit. The next
question that arises in our mind is how objects get into our software system
and how objects get created. At this point we get introduced to the most
fundamental structure in object oriented programming, the classes.
A java class is a
template or prototype which defines the outline of state and behavior for all
the objects belonging to that class. An instance of a class is called as object
and all the objects of a class will have common state and behavior.
A java class is to
an object is like a blue print is to a house. Any number of houses can be
constructed from a single blue print. In a similar way many objects can be
created from a single class. A class outlines the properties of an object.
Objects created from the same class show similar characteristics.
The attributes and
actions can be assigned only after an object is created. When an object is
created then the actual instance of the entity come into existence. Hence, a
java class can be called as a conceptual model of an entity which is universal
and non-specific.
Java class syntax:
class identifier
{
class body
}
Here identifier
specifies the name of the class. Class body consists of data members and method
definitions. Curly braces surround the class body.
A class is static,
whereas the data contained in an object can be dynamic. In a class, attributes
are set throughout the execution of the program.
Example:
class ExampleClass
{
//Data member
declaration
char ch;
int num;
double decimalnum;
void
exampleMethod1()
{
System.out.println(“Hello
Java”);
}
void
exampleMethod2()
{
System.out.println(“Javaeschool.com”);
}
}
In the above
example, ExampleClass is the class name. The class body contains 3 data members
and 2 member method implementations.
