Test if the sum of two ints is a power of two?

Question:

How to write a java program that 4 ints have been provided as input. Return true if the sum of any two of them is a power of 2.?

Code:

public class TestSums {
   public static void main(String[] args) {
 
      int vars[] = new int[args.length];
      for(int n=0;n<vars.length;n++){
         try {
            vars[n]= Integer.parseInt(args[n]);
         } catch (NumberFormatException e) { 
            System.out.println(args[n] + " is no a number.");
         }
      }
 
      for(int i=0;i<vars.length;i++){
         for(int j=i+1;j<vars.length;j++){
            System.out.print(vars[i] + "," + vars[j] + ": " );
            System.out.println(sumIsPowerOfTwo(vars[i],vars[j]));
         }
      }
   }
 
   static boolean sumIsPowerOfTwo(int x, int y) {
      int z = x + y;
      return ((z & (z -1)) == 0);
   }
}

Output:

$ java TestSums 2 4 6 8
2,4: false
2,6: true
2,8: false
4,6: false
4,8: false
6,8: false