[castor-dev] Strange NullPointerException

[cwd]

Hi all,     I am doing a very simple OQL execute in my servlet code(tomcat4.0 , Solaris8 , jdk1.3.1, poolman2.0.4). First time ,it functions well, but if I idle the tomcat for several minutes before I retry it, I got these exceptions. these code functions well under Window2k. please help me.   SELECT "U_USERINFO"."ID","U_USERINFO"."LOGIN","U_USERINFO"."PASSWD","U_USERINFO"."ISVALID","U_USERINFO"."TYPE","U_USERINFO"."BALANCE","U_USERINFO"."USERDETAILS","U_MONTHPAY"."ID","U_USERHISTORY"."ID" FROM "U_USERINFO","U_MONTHPAY","U_USERHISTORY" WHERE "U_USERINFO"."ID"="U_MONTHPAY"."USERID"(+) AND "U_USERINFO"."ID"="U_USERHISTORY"."USERID"(+) AND ("U_USERINFO"."LOGIN" = ? and "U_USERINFO"."TYPE" = ?) java.lang.NullPointerException         at oracle.jdbc.driver.OraclePreparedStatement.setString(OraclePreparedStatement.java:1125)         at oracle.jdbc.driver.OraclePreparedStatement.setObject(OraclePreparedStatement.java:1994)         at oracle.jdbc.driver.OraclePreparedStatement.setObject(OraclePreparedStatement.java:2200)         at com.codestudio.sql.PoolManPreparedStatement.setObject(Unknown Source)         at org.exolab.castor.jdo.engine.SQLEngine$SQLQuery.execute(SQLEngine.java:1581)         at org.exolab.castor.persist.TransactionContext.query(TransactionContext.java:644)         at org.exolab.castor.jdo.engine.OQLQueryImpl.execute(OQLQueryImpl.java:458)         at org.exolab.castor.jdo.engine.OQLQueryImpl.execute(OQLQueryImpl.java:405)         at ua.module.user.web.AuthenticateAction.doAction(AuthenticateAction.java:58)         at ua.module.web.BaseAction.perform(BaseAction.java:118)         at org.apache.struts.action.ActionServlet.processActionPerform(ActionServlet.java:1621)         at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1431)         at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:463)         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:243)         at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:566)         at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)         at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)         at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:201)         at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:566)         at org.apache.catalina.valves.CertificatesValve.invoke(CertificatesValve.java:246)         at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:564)         at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)         at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)         at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2344)         at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)         at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:566)         at org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.java:170)         at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:564)         at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:170)         at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:564)         at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:462)         at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:564)         at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)         at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)         at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:163)         at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:566)         at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)         at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)         at org.apache.catalina.connector.http.HttpProcessor.process(HttpProcessor.java:1011)         at org.apache.catalina.connector.http.HttpProcessor.run(HttpProcessor.java:1106)         at java.lang.Thread.run(Thread.java:484)