Know About Constructors in java...........
Constructors
in java:- a
constructor is one of the special member method and it is automatically /
implicitly called by JVM during object
creation time for placing our own values without placing default values.
Advantages
of Constructors:-
When we
develop the java application with the concept of constructors then such
applications will get the following advantages-
·
Constructors eliminate default values.
·
Constructors eliminate in calling ordinary method.
In other
word the purpose of constructor concept is to initialize the object.
Rules/Characteristic/properties:-
·
Constructor will be called implicitly/automatically during object
creation time.
·
Each and every constructor name is similar to class name.
·
Constructor will not return any value even void also(if we write any
return type then it will be treated as an ordinary method )
·
Constructor should not be static.(because whenever an object is created
constructors will be called each & every time)
·
Constructors in java programming will not participate in inheritance
process (because every constructor is mint for initializing its own class data
members )
·
The access modifier of the constructor may or may not be private.
(a) If the access modifier constructor is private
an object of the corresponding class can be created in same class context of
some other class.
(b) If the access modifier of the constructor
is not private then we can create an object of corresponding class in the same
class context and in another class context.
Types
of constructors in java:-
In java programming we have two types of
constructors they are ….
·
Default/parameter less/zero argument constructor.
·
Para metered constructor.
1. Default Constructor:- a constructor is said to be default
if at only if it will not take any parameters.
The
purpose of default constructor is to create multiple object with respect to
same class for placing same values.
Syntax:- class <clsname>
{
<clsname>()
{
Block of
statements(s)………….initialization
}
}
Ø Write a java program which
illustrates the concept of default constructor.
class Constructor
{
int a,b;
Constructor()
{
System.out.println("Constructor...........DC");
a=1;
b=2;
System.out.println("the
value of a="+a);
System.out.println("the
value of b="+b);
}
}
class ConstructorDemo
{
public static void
main(String k[])
{
Constructor
c1=new Constructor();
Constructor
c2=new Constructor();
Constructor
c3=new Constructor();
}
}
Note:- Whenever we create an object only with default constructor
then defining the default construction is optional whenever we create an object
with default constructor and if we are not defining default constructor then
JVM will call its own constructor known as system defined default constructor
& whose role is to place default values.
Rule1:- if we create an object with the default constructor and if we
define the default constructor then JVM will execute programmer defined default
constructor & places programmer defined values.
