String textToSplit = "This is an example sentence. Can sentences also be terminated "+
                       "with a questionmark? Sometimes punctuation does not terminate "+
                       "a sentence, e.g. when abbreviating.";

  // Regular expression to split text by punctuation adjacent to a capitalised letter.
  // Expression taken from http://www.codeproject.com/KB/vb/SentenceParserVB.aspx
  String[] sentences = textToSplit.split("(?<=['\"\"A-Za-z0-9][\\.\\!\\?])\\s+(?=[A-Z])");

  for (String sentence : sentences)
  {
    println(sentence);
  }