Help with function

Here is the function:

private static int CountHits(int userguess[], int adigit[], int digits,String args[]) throws Exception
{
      int Hits=0;
      int Misses=0;
      int x=0;

      for (x=0;x<digits;x++)
      {
            if (userguess[x]==adigit[x])
            {
                  Hits++;
            }
      }
//diagnostic
      String strChar = String.valueOf(args[0]);
                                                                        
if (strChar.equals("testing"))
      {
            
            x=0;
            System.out.print("DIAGNOSTIC:");
            for (x=0;x<digits;x++)
            {
                  System.out.print(adigit[x] + " ");  
            }

            System.out.print("\n");
            System.out.print("HIT RESULT:");
            for (x=0;x<digits;x++)
            {
                  if  (userguess[x]==adigit[x])
                  {
                        System.out.print("H ");  
                  }
                  else
                  {
                        System.out.print(". ");
                  }
            
            }
            System.out.print("\n");
      }
return Hits;

}

When I pass in this:
java Lab2 "testing"
everything works fine.

when i dont pass it in, I get an ArrayIndexOutOfBoundsException


how do i correct this?