Determining the Word Boundaries in a Unicode String
The word break iterator finds both the beginning and end of words. 

 
 BreakIterator iterator = 
   BreakIterator.getWordInstance(Locale.CANADA);
 iterator.setText("a sentence");
 
   for (int index=iterator.first(); index !=
      BreakIterator.DONE;
      
      index=iterator.next()) {
        process(index);
   }