423: Mainline

Conveniently, you can both declare and initialize the counter variable in the for statement itself, thus producing a more compact for loop:

public class Demonstrate { 
 public static void main (String argv[]) { 
  System.out.println(powerOf2(4)); 
 } 
 public static int powerOf2 (int n) { 
  int result = 1; 
  for (int counter = n; counter != 0; counter = counter - 1) { 
    result = 2 * result; 
  } 
  return result; 
 } 
}