code: public void addClass(String chargroup) {
          if (chargroup.length() > 0) {
              char equivChar = chargroup.charAt(0);
              char[] key = new char[2];
              key[1] = 0;
              for (int i = 0; i < chargroup.length(); i++) {
                  key[0] = chargroup.charAt(i);
                  classmap.insert(key, 0, equivChar);
              }
          }
      }
docs: Add a character class to the tree. It is used by
  {@link SimplePatternParser SimplePatternParser} as callback to
  add character classes. Character classes define the
  valid word characters for hyphenation. If a word contains
  a character not defined in any of the classes, it is not hyphenated.
  It also defines a way to normalize the characters in order
  to compare them with the stored patterns. Usually pattern
  files use only lower case characters, in this case a class
  for letter 'a', for example, should be defined as "aA", the first
  character being the normalization char.