Variable Number of Arguments to methods

Passing multiple values to the method is accomplished by using the array concept. We declare the method having array type parameter. When this method is invoked then an array is passed having multiple values. So to do this we have to define the array before invoking the method.

Now java has the enhanced version of method that can accept variable number of arguments without using any array type.

You declare the parameter like

Object  . . .  args

The method can have zero or more parameters. Here Object is the type of parameter and three periods indicate the compiler that this method will accept variable number of arguments when it is invoked. The args is the variable that holds the values into the array of Object. The length of the args will tell you that how many parameters were supplied.

Following program define the method print that will accepts different number of arguments while calling it and print them.

 public class VarArgs
{
    public static void print(Object ... args)
    {
        System.out.println("Printing passed arguments\n");
        for(Object obj:args)
        {
            System.out.println("  "+obj);
        }
    }
   
    public static void main(String ar[])
    {
        //passing 6 arguments
        print(213,"aaaa",768.989,"34hyuy",3423,3478);
        //passing no argument
        print();
        //passing 5 arguments
        print(1,2,3,4,5);
        //passing 2 arguments
        print("aa","asd");  
    }
}
/*OUTPUT
 Printing passed arguments

  213
  aaaa
  768.989
  34hyuy
  3423
  3478
Printing passed arguments

Printing passed arguments

  1
  2
  3
  4
  5
Printing passed arguments

  aa
  asd
Press any key to continue...
 */

You can use any type like interface or class. The Object type is the general type that can be used to pass any type values. If you want to pass specified type of arguments than you can declare the args of that type. The method will accept the argument of the same type as declared into arguments type.

There is following example that accepts the Double type values.

public class VarArgs2
{
    public static void print(Double ... args)
    {
        System.out.println("Printing sum of arguments\n");
       
        double d=0.0;
       
        for(Double val:args)
        {
            d=d+val;
        }
        System.out.println("  "+d);
    }
   
    public static void main(String ar[])
    {
        //passing 6 arguments
        print(21.3,345.345,768.989,76.77,342.3,34.78);
        //passing no argument
        print();
       
    }
}
/*OUTPUT
Printing sum of arguments

  1589.484
Printing sum of arguments

  0.0
 */