This document contains the detailed description that what vararg method is? Why it came in existence? What is it's advantage? When it is appropriate to use vararg method? and most of the important that the cases that should be considered before using vararg methods.

2.  Var-arg methods stands for Variable Number of Argument Methods.
Before var-arg either we use overloaded method or take an array
as the method parameter but it was not considered good because it
leads to the maintenance problem.
 Until 1.4v we can’t declare a method with variable number of
arguments. If there is a change in number of arguments,
compulsory we should go for new method. The drawback of this
approach is increased in length of the code & reduced readability.
 To overcome this problem SUN microsystems’s people introduced
var-arg methods in 1.5v. According to this we can declare a method
which can take variable number of argument, such type of methods
are called var-arg methods.

3. class Test
{
public static void method1(int x)
{
System.out.println("single int-arg method
invoked.");
}
public static void method1(int x, int y)
{
System.out.println("double int-arg method invoked.");
}
public static void main(String[] args)
{
method1(10);
method1(10,20);
}
}
Output:
single int-arg
method
invoked.
double int-arg
method
invoked.

4. class Test1
{
public static void method1(int... x)
{
System.out.println("var-arg method
invoked.");
}
public static void main(String[] args)
{
method1(10);
method1(10,20);
}
}
Output:
var-arg method
invoked.
var-arg method
invoked.

6.  m1(int… x)
 m1(int …x)
 m1(int…x)
 m1(int x…)
 m1(int. ..x)
 m1(int. x...)

7.  m1(int x, int… y)
 m1(String s, double… d)
 m1(int… x, int y)
 m1(String… s, double… d)

8. class Test
{
public static void m1(int... x)
{
System.out.println("var-arg method.");
}
public static void m1(int[] x)
{
System.out.println("general method.");
}
public static void main(String[] args)
{
method1();
}
}
CE:
cannot declare
both m1(int[])
and m1(int...) in
Test

9. class Test1
{
public static void m1(int... x)
{
System.out.println("var-arg method.");
}
public static void m1(int x)
{
System.out.println("general method.");
}
public static void main(String[] args)
{
m1();
m1(10,20);
m1(10);
}
}
Output:
var-arg method.
var-arg method.
general method.

10. class Test1
{
void varArg(int... x)
{
System.out.println(x[1]);
}
public static void main(String[] args)
{
Test t = new Test();
t.varArg(10,20,30,40,50);
}
}
Output:
20

11. The main advantage of var-arg method is, we don’t need to use
overloaded method. So, the length of the code will reduce.
If we don't know how many argument we will have to pass in the
method, var-arg method is the better approach.