code: public static String getMD5Checksum(String str, Charset charset) throws IOException {
  
  		InputStream is = new ByteArrayInputStream(str.getBytes(charset.name()));
  		return getMD5Checksum(is);
  	}
docs: Returns the MD5 Checksum of the string passed in parameter
  
  @param str
  the string content
  @param charset
  the content charset
  
  @return the Checksum of the input stream
  @throws IOException
  if an IO exception occurs