amoeba连接mysql--ERROR 2006 (HY000): MySQL server has gone away

amoeba version：amoeba-mysql-binary-2.1.0-RC5.tar.gz
mysql version：5.5.20
OS:Oracle Linux Server release 5.7
java version: "1.6.0_14"
Java(TM) SE Runtime Environment (build 1.6.0_14-b08)
Java HotSpot(TM) Server VM (build 14.0-b16, mixed mode)

amoeba 的安装和配置参考http://docs.hexnova.com/amoeba/index.html
安装和配置的过程比较简单，在此记录一个使用过程中遇到的问题：

[mysql@db01 ]$ mysql -uroot -pmysql -h192.168.0.18 -P8066
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 11416420
Server version: 5.1.45-mysql-amoeba-proxy-2.1.0-RC5
Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> use test;
No connection. Trying to reconnect...
Connection id:    11416420
Current database: *** NONE ***

mysql> select * from t1;
ERROR 2006 (HY000): MySQL server has gone away
No connection. Trying to reconnect...
Connection id:    11416420
Current database: test
ERROR 2006 (HY000): MySQL server has gone away
No connection. Trying to reconnect...
Connection id:    11416420
Current database: test
ERROR 2006 (HY000): MySQL server has gone away

amoeba日志中的错误：
2012-03-05 15:10:21,028 INFO  net.ServerableConnectionManager - Amoeba Monitor Server listening on /192.168.0.18:8634.
java.util.NoSuchElementException: Could not create a validated object, cause: ValidateObject failed
        at org.apache.commons.pool.impl.GenericObjectPool.borrowObject(GenericObjectPool.java:1191)
        at com.meidusa.amoeba.net.poolable.GenericObjectPool.borrowObject(GenericObjectPool.java:381)
        at com.meidusa.amoeba.mysql.handler.CommandMessageHandler.startSession(CommandMessageHandler.java:629)
        at com.meidusa.amoeba.mysql.handler.MySqlCommandDispatcher.handleMessage(MySqlCommandDispatcher.java:123)
        at com.meidusa.amoeba.mysql.net.MysqlClientConnection$2.run(MysqlClientConnection.java:291)
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
        at java.lang.Thread.run(Thread.java:619)
        
查了一些资料，修改了以下三个参数，重启后依然没起作用。
http://dev.mysql.com/doc/refman/5.5/en/error-lost-connection.html        
mysql>show variables like 'connect_timeout';
mysql>show variables like  'net_read_timeout';
mysql>show variables like  'max_allowed_packet';

仔细检查dbServers.xml配置后发现factoryConfig中
password             
默认是被注释掉的，注释取消后正常。

                        ${defaultManager}
                        64
                        128

                       
                        3306

                       
                        test

                       
                        root