我们有一个使用 Apache DBCP 进行连接池的 Spring 应用程序。我们的应用程序已经投入生产将近一年了，没有任何问题。但是，在过去的几周中，该应用程序已多次冻结。（通过冻结，我的意思是不处理任何请求。）通过重新启动托管应用程序的 Glassfish 域暂时解决了该问题。
我们正在监视此应用程序的内存（堆 + 非堆）和 CPU 利用率。这里似乎没有什么不寻常的地方。然而，我们注意到，当我们重新启动域时，我们会在日志文件中收到类似于本文底部的异常消息。
我指出我们正在使用 DBCP，因为每个 NPE 都在堆栈顶部报告 borrowObject 方法。在任何应用程序关闭期间，它们中的每一个都在同一毫秒内发生。
我们注意到过去发生了一些这样的情况（使用这样的 NPE 关闭），但是当应用程序冻结时，总是有五个。我们不认为这是巧合，这是相同数量的 HTTPSSLWorkerThreads 处理对应用程序的请求。
如果有人知道是什么原因造成的，以及如何解决它，我们将不胜感激。
[#|2009-09-27T12:17:12.209-0400|SEVERE|sun-appserver9.1|javax.enterprise.system.container.web|_ThreadID=20;_ThreadName=httpSSLWorkerThread-443-4;_RequestID=25b115cb-de08-4ad4-bfdb-f76eb13b4bbe;|StandardWrapperValve[spring-dispatcher]: PWC1406: Servlet.service() for servlet spring-dispatcher threw exception
java.lang.NullPointerException
at org.apache.commons.pool.impl.GenericObjectPool.borrowObject(GenericObjectPool.java:788)
at org.apache.commons.dbcp.PoolingDataSource.getConnection(PoolingDataSource.java:95)
at org.apache.commons.dbcp.BasicDataSource.getConnection(BasicDataSource.java:540)
at org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(DataSourceUtils.java:113)
at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:79)
at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:552)
at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:616)
at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:645)
at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:653)
at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:685)
at org.springframework.jdbc.core.simple.SimpleJdbcTemplate.query(SimpleJdbcTemplate.java:187)
at stimpl.dao.ProjectDAO.getSearchResults(ProjectDAO.java:153)
at stimpl.service.StimPlService.getSearchResults(StimPlService.java:69)
at stimpl.mvc.search.ShowResultsController.handleRequestInternal(ShowResultsController.java:44)
at org.springframework.web.servlet.mvc.AbstractController.handleRequest(AbstractController.java:153)
at org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:48)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:874)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:808)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:476)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:431)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:718)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:831)
at org.apache.catalina.core.ApplicationFilterChain.servletService(ApplicationFilterChain.java:411)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:317)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:198)
at org.acegisecurity.securechannel.ChannelProcessingFilter.doFilter(ChannelProcessingFilter.java:138)
at org.acegisecurity.util.FilterToBeanProxy.doFilter(FilterToBeanProxy.java:98)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:198)
at org.acegisecurity.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:265)
at org.acegisecurity.intercept.web.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:107)
at org.acegisecurity.intercept.web.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:72)
at org.acegisecurity.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:275)
at org.acegisecurity.ui.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:124)
at org.acegisecurity.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:275)
at org.acegisecurity.providers.anonymous.AnonymousProcessingFilter.doFilter(AnonymousProcessingFilter.java:125)
at org.acegisecurity.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:275)
at org.acegisecurity.wrapper.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:81)
at org.acegisecurity.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:275)
at org.acegisecurity.ui.AbstractProcessingFilter.doFilter(AbstractProcessingFilter.java:271)
at org.acegisecurity.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:275)
at org.acegisecurity.ui.logout.LogoutFilter.doFilter(LogoutFilter.java:110)
at org.acegisecurity.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:275)
at org.acegisecurity.context.HttpSessionContextIntegrationFilter.doFilter(HttpSessionContextIntegrationFilter.java:249)
at org.acegisecurity.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:275)
at org.acegisecurity.util.FilterChainProxy.doFilter(FilterChainProxy.java:149)
at org.acegisecurity.util.FilterToBeanProxy.doFilter(FilterToBeanProxy.java:98)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:198)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:288)
at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:271)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:202)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:632)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:577)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:94)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:206)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:632)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:577)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:571)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:1080)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:150)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:632)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:577)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:571)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:1080)
at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:270)
at com.sun.enterprise.web.connector.grizzly.DefaultProcessorTask.invokeAdapter(DefaultProcessorTask.java:637)
at com.sun.enterprise.web.connector.grizzly.DefaultProcessorTask.doProcess(DefaultProcessorTask.java:568)
at com.sun.enterprise.web.connector.grizzly.DefaultProcessorTask.process(DefaultProcessorTask.java:813)
at com.sun.enterprise.web.connector.grizzly.DefaultReadTask.executeProcessorTask(DefaultReadTask.java:339)
at com.sun.enterprise.web.connector.grizzly.ssl.SSLReadTask.process(SSLReadTask.java:440)
at com.sun.enterprise.web.connector.grizzly.ssl.SSLReadTask.doTask(SSLReadTask.java:228)
at com.sun.enterprise.web.connector.grizzly.TaskBase.run(TaskBase.java:265)
at com.sun.enterprise.web.connector.grizzly.ssl.SSLWorkerThread.run(SSLWorkerThread.java:106)
|#]