DCN监听 java中获取到变化的表名为三个？

用的oracle DCN监听数据库变化的表，为什么打印出来的表名是？？？
我写的哪里不对么？是在刚得到databaseChangeEvent的时候就已经是三个问号了，
但是rowid正常获取出来了，请求各位帮助，谢谢。

 package com.dtqy.dcn.test;

import java.sql.SQLException;
import java.util.Properties;

import oracle.jdbc.OracleStatement;
import oracle.jdbc.dcn.DatabaseChangeListener;
import oracle.jdbc.dcn.DatabaseChangeRegistration;
import oracle.jdbc.driver.OracleConnection;
import oracle.jdbc.pool.OracleDataSource;

public class Test {
    public static void main(String[] args) throws SQLException {
        OracleDataSource dataSource = new OracleDataSource();
        dataSource.setUser("jsxl_admin");
        dataSource.setPassword("root");
        dataSource.setURL("jdbc:oracle:thin:@124.130.149.119:1521:orcl");
        final OracleConnection conn = (OracleConnection) dataSource
                .getConnection();
        Properties prop = new Properties();
        prop.setProperty(OracleConnection.DCN_NOTIFY_ROWIDS, "true");// 要取得更改记录的rowid
        // 设置超时，这里是1个小时，届时数据库和驱动器的资源自动释放。如果为0或不设置，则用不过期，直到程序停止监听，当数据库发送更新通知时，因为没有监听端口，数据库随后释放资源
        prop.setProperty(OracleConnection.NTF_TIMEOUT, "0");
        DatabaseChangeRegistration databaseChangeRegistration = conn
                .registerDatabaseChangeNotification(prop);
        DatabaseChangeListener databaseChangeListener = new DataBaseChangeListenerTest();
        databaseChangeRegistration.addListener(databaseChangeListener);
        OracleStatement statement = (OracleStatement) conn.createStatement();
        statement.setDatabaseChangeRegistration(databaseChangeRegistration);
        statement.executeQuery("select * from DTQY_JXKH_CJ_RY t where 1=2");
        statement.executeQuery("select * from DTQY_JXKH_CL where 1=2");
        statement.close();
        conn.close();
        System.err.println("数据库更改通知开启：");
    }
}

 package com.dtqy.dcn.test;

import java.util.Date;

import org.apache.commons.lang.time.DateFormatUtils;

import com.dtqy.kettle.test.JavaCallKettle;

import oracle.jdbc.dcn.DatabaseChangeEvent;
import oracle.jdbc.dcn.DatabaseChangeListener;
import oracle.jdbc.dcn.RowChangeDescription;
import oracle.jdbc.dcn.RowChangeDescription.RowOperation;
import oracle.jdbc.dcn.TableChangeDescription;
import oracle.sql.ROWID;

public class DataBaseChangeListenerTest implements DatabaseChangeListener {
    @Override
    public void onDatabaseChangeNotification(
            DatabaseChangeEvent databaseChangeEvent) {
        TableChangeDescription[] tds = databaseChangeEvent
                .getTableChangeDescription();
        System.out.println("============================="
                + DateFormatUtils.format(new Date(), "yyyy-MM-dd HH:mm:ss")
                + "=============================");
        System.out.println("'TableChangeDescription'(数据表的变化次数):" + tds.length);
        for (TableChangeDescription td : tds) {
            System.out.println("数据库表id：" + td.getObjectNumber());
            System.out.println("数据表名称：" + td.getTableName());
            // 获得返回的行级变化描述通知 行id、影响这一行的DML操作(行是插入、更新或删除的一种)
            RowChangeDescription[] rds = td.getRowChangeDescription();
            for (RowChangeDescription rd : rds) {
                RowOperation rowOperation = rd.getRowOperation();
                System.out.println("数据库表行级变化：" + rowOperation.toString());
                ROWID rowid = rd.getRowid();
                System.out.println(rowid.stringValue());
                //JavaCallKettle.runTransfer(rowid.stringValue());
            }
        }
    }
}

=============================2016-01-05 10:35:20=============================
'TableChangeDescription'(数据表的变化次数):1
数据库表id：53364
数据表名称：???
数据库表行级变化：UPDATE
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