Question

How do you duplicate this feature in Java?

In C#, you could use the params keyword to specify variable parameter lists for functions.

How do you do that in Java?

Or do you have to resort to multiple overloads?

Answer 1

C# code:

double Average(params double[] nums) {
  var sum = 0.0;
  foreach(var num in nums) 
    sum += num;
  return sum / nums.Length;
}

Equivalent Java code:

double average(double... nums) {
  double sum = 0.0;
  for(double num : nums) 
    sum += num;
  return sum / nums.length;
}

This feature is known as varargs. You can read more about it here.