Can anyone explain:

1. Why the two patterns used below give different results? (answered below)
2. Why the 2nd example gives a group count of 1 but says the start and end of group 1 is -1?

 public void testGroups() throws Exception
 {
  String TEST_STRING = "After Yes is group 1 End";
  {
   Pattern p;
   Matcher m;
   String pattern="(?:Yes|No)(.*)End";
   p=Pattern.compile(pattern);
   m=p.matcher(TEST_STRING);
   boolean f=m.find();
   int count=m.groupCount();
   int start=m.start(1);
   int end=m.end(1);

   System.out.println("Pattern=" + pattern + "\t Found=" + f + " Group count=" + count + 
     " Start of group 1=" + start + " End of group 1=" + end );
  }

  {
   Pattern p;
   Matcher m;

   String pattern="(?:Yes)|(?:No)(.*)End";
   p=Pattern.compile(pattern);
   m=p.matcher(TEST_STRING);
   boolean f=m.find();
   int count=m.groupCount();
   int start=m.start(1);
   int end=m.end(1);

   System.out.println("Pattern=" + pattern + "\t Found=" + f + " Group count=" + count + 
     " Start of group 1=" + start + " End of group 1=" + end );
  }

 }

Which gives the following output:

Pattern=(?:Yes|No)(.*)End  Found=true Group count=1 Start of group 1=9 End of group 1=21
Pattern=(?:Yes)|(?:No)(.*)End  Found=true Group count=1 Start of group 1=-1 End of group 1=-1