Constructor
overloading in Java. If you want to get knowledge and clear understanding about Java constructor overloading example. Then its a best place for you, here i will teach you in
detail about Java constructor overloading with very easy to understand examples.
Overload Constructor in Java with Examples
In
Java language, we can overload constructor just like we can overload a method.
To understand constructor overloading in detail, we must first have to know
about what is actually overloading in Java. In Java, methods as well as
constructors both can be overloaded, which means having more than one method or
constructor with the same name in same program.
Reason
behind this is that using same name for methods and constructors, we can take
different tasks from them. For example, we can have a method or constructor
that cannot take any argument and we can have a method or a constructor with
same name but can accept arguments.
We
can use default constructor, constructor with single parameter, constructor
with 2 parameters etc in constructor overloading to achieve different tasks but
with same name.
class
A
{
A() //constructor with no argument
{
}
A(int a) //constructor with one
argument of type int
{
}
A(int x,int y) //constructor with two
argument of type int
{
}
A(String name) //constructor with one
argument of type String
{
}
}
Constructor
Overloading Program
class
A
{
int
a,b;
A() //Constructor without any argument
{
a = 10;
b = 20;
System.out.println(a + “ “ + b);
}
A(int x, int y) //Constructor with 2
parameters
{
a = x;
b = y;
System.out.println(a + “ “ + b);
}
public static void main(String ar[])
{
A obj = new A (); //this will call the
non-parameterized constructor
A obj2 = new A (100, 200); //this will
call the parameterized constructor
}
}
Output
will be
10
20
100
200
Example
Program 2
In
this example, we will focus on default constructor which is actually created by
Java itself when user does not write code for his own constructor in class
public
class A
{
int a;
A (int x)
{
a = x;
System.out.println(a);
}
public static void main (String ar[])
{
A object = new A (); //here we are
calling a constructor which will not accept any argument and this constructor
is not present in our class, so we will get error here
}
}
Output
will be
Error, because we don’t have any constructor in class which accept no argument
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