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tomcat connection pool exception ,help!

chu chen
Greenhorn

Joined: Oct 15, 2003
Posts: 1
I use tomcat4.1,sybase,
jconn2.jar has been put in common/lib,
when tomcat service start,run a test program,it reports exception:
org.apache.commons.dbcp.SQLNestedException: Cannot get a connection, pool exhausted, cause:
java.util.NoSuchElementException: Could not create a validated object
at org.apache.commons.pool.impl.GenericObjectPool.borrowObject(GenericObjectPool.java:851)
at org.apache.commons.dbcp.PoolingDataSource.getConnection(PoolingDataSource.java:140)
at org.apache.commons.dbcp.BasicDataSource.getConnection(BasicDataSource.java:518)
at com.hy.db.testdb.performTask(testdb.java:54)
at com.hy.db.testdb.doGet(testdb.java:26)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:740)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:247)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:256)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2414)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:180)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.java:171)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:163)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:174)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.coyote.tomcat4.CoyoteAdapter.service(CoyoteAdapter.java:199)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:828)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:700)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:584)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
at java.lang.Thread.run(Unknown Source)

server.xml:
<Engine className="org.apache.catalina.core.StandardEngine" debug="0" defaultHost="localhost" mapperClass="org.apache.catalina.core.StandardEngineMapper" name="Standalone">
<Host className="org.apache.catalina.core.StandardHost" appBase="webapps" autoDeploy="true" configClass="org.apache.catalina.startup.ContextConfig" contextClass="org.apache.catalina.core.StandardContext" debug="0" deployXML="true" errorReportValveClass="org.apache.catalina.valves.ErrorReportValve" liveDeploy="true" mapperClass="org.apache.catalina.core.StandardHostMapper" name="localhost" unpackWARs="true">

<Context className="org.apache.catalina.core.StandardContext" cachingAllowed="true" charsetMapperClass="org.apache.catalina.util.CharsetMapper" cookies="true" crossContext="true" debug="5" displayName="MonitorModule" docBase="D:/Program Files/Apache Group/Tomcat 4.1/webapps/MonitorModule" mapperClass="org.apache.catalina.core.StandardContextMapper" path="/MonitorModule" privileged="true" reloadable="true" swallowOutput="true" useNaming="true" wrapperClass="org.apache.catalina.core.StandardWrapper">
<Resource auth="Container" description="Connection Pool" name="jdbc/MonitorDS" scope="Shareable" type="javax.sql.DataSource"/>
<ResourceParams name="jdbc/MonitorDS">
<parameter>
<name>factory</name>
<value>org.apache.commons.dbcp.BasicDataSourceFactory</value>
</parameter>
<parameter>
<name>url</name>
<value>jdbc:sybase:Tds:192.168.0.171:9988/my_data</value>
</parameter>
<parameter>
<name>password</name>
<value></value>
</parameter>
<parameter>
<name>maxActive</name>
<value>10</value>
</parameter>
<parameter>
<name>maxWait</name>
<value>5000</value>
</parameter>
<parameter>
<name>driverClassName</name>
<value>com.sybase.jdbc2.jdbc.SybDriver</value>
</parameter>
<parameter>
<name>username</name>
<value>sa</value>
</parameter>
<parameter>
<name>maxIdle</name>
<value>5</value>
</parameter>
</ResourceParams>
</Context>
</Engine>
</Service>

web.xml:
<resource-ref>
<description>Connection Pool</description>
<res-ref-name>jdbc/MonitorDS</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>

test program:
Context context = new InitialContext();
Context envContext = (Context)context.lookup("java:/comp/env");
ds = (DataSource) envContext.lookup("jdbc/MonitorDS");
if(ds!=null){
out.println("get datadource ok!" + ds.toString());
}else{
out.println("get datasource failed!" + ds.toString());
}
conn = ds.getConnection();
server.xml:server.xml:web.xml:test program
Paulo Nascimento
Greenhorn

Joined: Jul 22, 2004
Posts: 2
If you set the maxWait property in tomcat server.xml file (number in milliseconds), and the pool reach the max number of connections allowed, it will block 'maxWait' milliseconds and retry obtain a connection from pool. If no one is available, it will generate this exception.
If you want tomcat to block until a connection become available, you should not set maxWait parameter in server.xml file.
If you want more information about this, I suggest you to look for commons-pool documentation. Commons-pool is the jakarta pool api used internally by tomcat.

Best Regards,
Paulo Nascimento
Atos Origin Brazil

Originally posted by chu chen:
I use tomcat4.1,sybase,
jconn2.jar has been put in common/lib,
when tomcat service start,run a test program,it reports exception:
org.apache.commons.dbcp.SQLNestedException: Cannot get a connection, pool exhausted, cause:
java.util.NoSuchElementException: Could not create a validated object
at org.apache.commons.pool.impl.GenericObjectPool.borrowObject(GenericObjectPool.java:851)
at org.apache.commons.dbcp.PoolingDataSource.getConnection(PoolingDataSource.java:140)
at org.apache.commons.dbcp.BasicDataSource.getConnection(BasicDataSource.java:518)
at com.hy.db.testdb.performTask(testdb.java:54)
at com.hy.db.testdb.doGet(testdb.java:26)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:740)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:247)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:256)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2414)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:180)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.java:171)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:163)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:174)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.coyote.tomcat4.CoyoteAdapter.service(CoyoteAdapter.java:199)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:828)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:700)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:584)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
at java.lang.Thread.run(Unknown Source)

server.xml:
<Engine className="org.apache.catalina.core.StandardEngine" debug="0" defaultHost="localhost" mapperClass="org.apache.catalina.core.StandardEngineMapper" name="Standalone">
<Host className="org.apache.catalina.core.StandardHost" appBase="webapps" autoDeploy="true" configClass="org.apache.catalina.startup.ContextConfig" contextClass="org.apache.catalina.core.StandardContext" debug="0" deployXML="true" errorReportValveClass="org.apache.catalina.valves.ErrorReportValve" liveDeploy="true" mapperClass="org.apache.catalina.core.StandardHostMapper" name="localhost" unpackWARs="true">

<Context className="org.apache.catalina.core.StandardContext" cachingAllowed="true" charsetMapperClass="org.apache.catalina.util.CharsetMapper" cookies="true" crossContext="true" debug="5" displayName="MonitorModule" docBase="D:/Program Files/Apache Group/Tomcat 4.1/webapps/MonitorModule" mapperClass="org.apache.catalina.core.StandardContextMapper" path="/MonitorModule" privileged="true" reloadable="true" swallowOutput="true" useNaming="true" wrapperClass="org.apache.catalina.core.StandardWrapper">
<Resource auth="Container" description="Connection Pool" name="jdbc/MonitorDS" scope="Shareable" type="javax.sql.DataSource"/>
<ResourceParams name="jdbc/MonitorDS">
<parameter>
<name>factory</name>
<value>org.apache.commons.dbcp.BasicDataSourceFactory</value>
</parameter>
<parameter>
<name>url</name>
<value>jdbc:sybase:Tds:192.168.0.171:9988/my_data</value>
</parameter>
<parameter>
<name>password</name>
<value></value>
</parameter>
<parameter>
<name>maxActive</name>
<value>10</value>
</parameter>
<parameter>
<name>maxWait</name>
<value>5000</value>
</parameter>
<parameter>
<name>driverClassName</name>
<value>com.sybase.jdbc2.jdbc.SybDriver</value>
</parameter>
<parameter>
<name>username</name>
<value>sa</value>
</parameter>
<parameter>
<name>maxIdle</name>
<value>5</value>
</parameter>
</ResourceParams>
</Context>
</Engine>
</Service>

web.xml:
<resource-ref>
<description>Connection Pool</description>
<res-ref-name>jdbc/MonitorDS</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>

test program:
Context context = new InitialContext();
Context envContext = (Context)context.lookup("java:/comp/env");
ds = (DataSource) envContext.lookup("jdbc/MonitorDS");
if(ds!=null){
out.println("get datadource ok!" + ds.toString());
}else{
out.println("get datasource failed!" + ds.toString());
}
conn = ds.getConnection();
server.xml:server.xml:web.xml:test program
Paulo Nascimento
Greenhorn

Joined: Jul 22, 2004
Posts: 2
Sorry, I made a mistake.
It seems tomcat will assume maxWait of 5000 in case of we don't provide it.
If we set this property with -1 value, tomcat should block until a connection become available, but I've had problems using tomcat (v 5.18) pool with oracle. When tomcat reached the max connection number, it blocked undefinetelly.

I am facing this problem yet and I didn't reach the ideal solution.

Paulo Nascimento

Originally posted by chu chen:
I use tomcat4.1,sybase,
jconn2.jar has been put in common/lib,
when tomcat service start,run a test program,it reports exception:
org.apache.commons.dbcp.SQLNestedException: Cannot get a connection, pool exhausted, cause:
java.util.NoSuchElementException: Could not create a validated object
at org.apache.commons.pool.impl.GenericObjectPool.borrowObject(GenericObjectPool.java:851)
at org.apache.commons.dbcp.PoolingDataSource.getConnection(PoolingDataSource.java:140)
at org.apache.commons.dbcp.BasicDataSource.getConnection(BasicDataSource.java:518)
at com.hy.db.testdb.performTask(testdb.java:54)
at com.hy.db.testdb.doGet(testdb.java:26)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:740)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:247)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:256)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2414)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:180)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.java:171)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:163)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:174)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.coyote.tomcat4.CoyoteAdapter.service(CoyoteAdapter.java:199)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:828)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:700)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:584)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
at java.lang.Thread.run(Unknown Source)

server.xml:
<Engine className="org.apache.catalina.core.StandardEngine" debug="0" defaultHost="localhost" mapperClass="org.apache.catalina.core.StandardEngineMapper" name="Standalone">
<Host className="org.apache.catalina.core.StandardHost" appBase="webapps" autoDeploy="true" configClass="org.apache.catalina.startup.ContextConfig" contextClass="org.apache.catalina.core.StandardContext" debug="0" deployXML="true" errorReportValveClass="org.apache.catalina.valves.ErrorReportValve" liveDeploy="true" mapperClass="org.apache.catalina.core.StandardHostMapper" name="localhost" unpackWARs="true">

<Context className="org.apache.catalina.core.StandardContext" cachingAllowed="true" charsetMapperClass="org.apache.catalina.util.CharsetMapper" cookies="true" crossContext="true" debug="5" displayName="MonitorModule" docBase="D:/Program Files/Apache Group/Tomcat 4.1/webapps/MonitorModule" mapperClass="org.apache.catalina.core.StandardContextMapper" path="/MonitorModule" privileged="true" reloadable="true" swallowOutput="true" useNaming="true" wrapperClass="org.apache.catalina.core.StandardWrapper">
<Resource auth="Container" description="Connection Pool" name="jdbc/MonitorDS" scope="Shareable" type="javax.sql.DataSource"/>
<ResourceParams name="jdbc/MonitorDS">
<parameter>
<name>factory</name>
<value>org.apache.commons.dbcp.BasicDataSourceFactory</value>
</parameter>
<parameter>
<name>url</name>
<value>jdbc:sybase:Tds:192.168.0.171:9988/my_data</value>
</parameter>
<parameter>
<name>password</name>
<value></value>
</parameter>
<parameter>
<name>maxActive</name>
<value>10</value>
</parameter>
<parameter>
<name>maxWait</name>
<value>5000</value>
</parameter>
<parameter>
<name>driverClassName</name>
<value>com.sybase.jdbc2.jdbc.SybDriver</value>
</parameter>
<parameter>
<name>username</name>
<value>sa</value>
</parameter>
<parameter>
<name>maxIdle</name>
<value>5</value>
</parameter>
</ResourceParams>
</Context>
</Engine>
</Service>

web.xml:
<resource-ref>
<description>Connection Pool</description>
<res-ref-name>jdbc/MonitorDS</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>

test program:
Context context = new InitialContext();
Context envContext = (Context)context.lookup("java:/comp/env");
ds = (DataSource) envContext.lookup("jdbc/MonitorDS");
if(ds!=null){
out.println("get datadource ok!" + ds.toString());
}else{
out.println("get datasource failed!" + ds.toString());
}
conn = ds.getConnection();
server.xml:server.xml:web.xml:test program
 
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