Finding Spaces, Newlines and Tabs with charAt()

This works for me:

  char c = txt.charAt(strt);
  if (c == ' ' || c == '\t' || c == '\n' || c == '\r')
    System.out.println("Found one at " + strt);

Yours works too, although it's a bit harder to follow. Why it doesn't work for you I don't know - maybe the string is badly formed? Are you sure you actually have tabs and stuff in it?