code: public String getID() {
          byte[] genBytes = new byte[_byteArraySize];
          synchronized (_random) {
              _random.nextBytes(genBytes);
          }
          String id = convertSessionIdBytesToSessionId(genBytes, _sessionIDLength);
          if (tc.isDebugEnabled()) {
              Tr.debug(tc, "sessionID=" + id);
          }
          return id;
      }
docs: ----------------------------------------