Java Database Connectivity (JDBC)

Hello, I have an oracle RAC 10gR2 SE (10.2.0.3) with 3 nodes on Suse Linux 10. I had various java web applications with tomcat 6.X that it's use dbcp to connect to oracle. Sometimes, I had several problems with my oracles nodes, and some nodes reboot out planned. The most time when an node was reboot (out planned) the java application hangs and I have to restart the tomcat.

In the server.xml on the tomcat, we had the follow:

    <Resource auth="Container" 
	driverClassName="oracle.jdbc.driver.OracleDriver"  
	maxActive="50"  maxIdle="10" maxWait="5" removeAbandoned="true" removeAbandonedTimeout="60" 
	type="javax.sql.DataSource" name="jdbc/TrewaDS" 
	username="TREWA16" password="" 
	url="jdbc:oracle:thin:@(DESCRIPTION=(LOAD_BALANCE=ON)(ADDRESS=(PROTOCOL=TCP)(HOST=172.22.8.250)(PORT=1521))(ADDRESS=(PROTOCOL=TCP)(HOST=172.22.8.236)(PORT=1521))(CONNECT_DATA=(SERVICE_NAME=SRV_WANDA)))" 
	/>

Because of that, I'm looking for internet and I read that ucp uses FCF and is better that dbcp in that cases. Then, I decided to change the dbcp pool for ucp pool. For that, I replacethe ojdbc14.jar for odjbc6.jar, and add ons.jar and ucp.jar in the classpath of tomcat (tomcat/common/lib). In the server.xml on tomcat, I replace my datasource for the follow:

<Resource name="jdbc/TrewaDS"      
	auth="Container"     
	factory="oracle.ucp.jdbc.PoolDataSourceImpl"     
	type="oracle.ucp.jdbc.PoolDataSource"     
	description="FCF Trewa16"     
	connectionFactoryClassName="oracle.jdbc.pool.OracleDataSource"     
	connectionWaitTimeout="30"     
	minPoolSize="5"     
	maxPoolSize="25"     
	inactiveConnectionTimeout="20"     
	timeoutCheckInterval="60"     
	fastConnectionFailoverEnabled="true"     
	onsConfiguration="nodes=172.22.8.249:6200,172.22.8.243:6200,172.22.8.235:6200"     
	user="TREWA16"      
	password=""     
	url="jdbc:oracle:thin:@(DESCRIPTION=(LOAD_BALANCE=ON)(ADDRESS=(PROTOCOL=TCP)(HOST=172.22.8.250)(PORT=1521))(ADDRESS=(PROTOCOL=TCP)(HOST=172.22.8.236)(PORT=1521))(CONNECT_DATA=(SERVICE_NAME=SRV_WANDA)))" 
	connectionPoolName="trewaConnectionPool"      
	validateConnectionOnBorrow="true"     
	sqlForValidateConnection="select 1 from DUAL" /> 

And I execute the follow in the database:

EXECUTE DBMS_SERVICE.MODIFY_SERVICE (service_name => 'SRV_WANDA', goal => DBMS_SERVICE.GOAL_THROUGHPUT, clb_goal => DBMS_SERVICE.CLB_GOAL_SHORT);

Then I can connect correctly with oracle. My applications looks fine. However, various minutes later, in the catalina.out (tomcat's logs) appear the follow:

[2012-07-05 08:45:59,157] trewa.util.Log ERROR:  (trewa.bd.ConexionTrewa - ) - Se ha producido una excepción al obtener la conexión: oracle.ucp.UniversalConnectionPlException: Todas las conexiones de Universal Connection Pool están en uso
[2012-07-05 08:45:59,158] trewa.util.Log ERROR:  (trewa.bd.trapi.trapiui.TrAPIUIOraImpl - ) - java.lang.NullPointerException
        at trewa.util.TrUtil.createPreparedStatement(TrUtil.java:74)
        at trewa.bd.trapi.trapiui.TrAPIUIImpl.recorrerFaseActExp(TrAPIUIImpl.java:4108)
        at trewa.bd.trapi.trapiui.TrAPIUIImpl.obtenerFaseActualExpediente(TrAPIUIImpl.java:3989)
        at es.juntadeandalucia.plataforma.expediente.ExpedienteTrewa.getFaseActual(ExpedienteTrewa.java:277)
        at es.juntadeandalucia.plataforma.actions.expediente.ConsultaExpedienteAction.accesoExpediente(ConsultaExpedienteAction.java:95)
        at sun.reflect.GeneratedMethodAccessor392.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)

In the message, says thar all connections in Universal Connection Pool already are in use. Then I increase the limit of maxPoolSize from 25 to 100. The java web applications have 400 users aprox. When I increase the limit, don't appear the errors, but then my nodes increase the memory and swap, oracle send alerts that memory are in 99% (I know that I have to buy more ram, but for now can't do it). However if I use dbcp oracle don't sends me any alert of memory. I suppose that with ucp I have to stablish very connections and don't remove any.

How can I configure the ucp? Should I use ucp or dbcp? Can I configure dbcp for avoid the applications hangs when a node is reboot?

anyone can help me??
Thanks in advanced.