this.ds = ds; this.tm = tm; bytesStoredAs = BYTES_AS_BYTES; sqlProperties = new Properties();
this(null, null);
   public JDBCTransactionLog(DataSource ds, TransactionManager tm) throws Exception   {      this.ds = ds;      this.tm = tm;      bytesStoredAs = BYTES_AS_BYTES;      sqlProperties = new Properties();   }