我正在尝试将 Oracle 通用连接池 (UCP) 与 tomcat6 集成。服务器配置如下：
服务器.xml
<Resource name="jdbc/MyDB"
auth="Container"
factory="oracle.ucp.jdbc.PoolDataSourceImpl"
type="oracle.ucp.jdbc.PoolDataSource"
description="Oracle Universal Connection Pool"
connectionFactoryClassName="oracle.jdbc.pool.OracleDataSource"
minPoolSize="1"
maxPoolSize="5"
inactiveConnectionTimeout="20"
connectionPoolName="UCPPool"
validateConnectionOnBorrow="true"
sqlForValidateConnection="select 1 from DUAL"
fastConnectionFailoverEnabled="true"
onsConfiguration="nodes=test11grac1.example.com:6200,test11grac2.example.com:6200"
user="test"
password="XXXX"
url="jdbc:oracle:thin:@test11g-cluster.example.com:1521/testdb"/>
上下文.xml
<ResourceLink name="jdbc/MyDB" global="jdbc/MyDB" />
最初，此配置运行良好。连接均匀地分布在两个 RAC 实例中，当一个实例出现故障时，所有后续请求都指向正在工作的一个实例。
经过一夜的空闲时间后，对连接池的所有请求都导致以下异常：
Caused by: java.lang.NullPointerException: null
at oracle.ucp.jdbc.oracle.OracleJDBCConnectionPool.createOnePooledConnection(OracleJDBCConnectionPool.java:1260) ~[ucp.jar:11.2.0.3.0]
at oracle.ucp.common.UniversalConnectionPoolImpl.borrowConnectionWithoutCountingRequests(UniversalConnectionPoolImpl.java:339) ~[ucp.jar:11.2.0.3.0]
at oracle.ucp.common.UniversalConnectionPoolImpl.borrowConnectionAndValidate(UniversalConnectionPoolImpl.java:168) ~[ucp.jar:11.2.0.3.0]
at oracle.ucp.common.UniversalConnectionPoolImpl.borrowConnection(UniversalConnectionPoolImpl.java:143) ~[ucp.jar:11.2.0.3.0]
at oracle.ucp.jdbc.JDBCConnectionPool.borrowConnection(JDBCConnectionPool.java:157) ~[ucp.jar:11.2.0.3.0]
at oracle.ucp.jdbc.PoolDataSourceImpl.getConnection(PoolDataSourceImpl.java:931) ~[ucp.jar:11.2.0.3.0]
at oracle.ucp.jdbc.PoolDataSourceImpl.getConnection(PoolDataSourceImpl.java:873) ~[ucp.jar:11.2.0.3.0]
at oracle.ucp.jdbc.PoolDataSourceImpl.getConnection(PoolDataSourceImpl.java:863) ~[ucp.jar:11.2.0.3.0]
at org.hibernate.ejb.connection.InjectedDataSourceConnectionProvider.getConnection(InjectedDataSourceConnectionProvider.java:46) ~[hibernate-entitymanager-3.4.0.GA.jar:3.4.0.GA]
什么可能导致此异常，是否有任何解决方法？