code: private static synchronized void lazyInit() {
  		if (registry==null) {
  			InputStream isXml = ProteinModification.class.getResourceAsStream(DIR_XML_PTM_LIST);
  			lazyInit(isXml);
  		}
  	}
docs: Lazy Initialization the static variables and register common modifications.
  just opens the stream to ptm_list.xml and delegates to lazyInit(InputStream) for parsing.