Concurrent usage of system session

[Markus Joschko <ma...@gmail.com>]

Hi,
while having debug logging enabled in a sling application, I found the
following stacktrace.
It's appearing regularly during login. Maybe somebody has some
pointers what the session-system-2 is and which circumstances
might be responsible for the concurrent usage.
Does it do any harm apart from blocking the thread?


12.07.2011 16:32:00.242 *DEBUG* [http-8080-9]
org.apache.jackrabbit.core.session.SessionState Attempt to perform
item.getPath() while another thread is concurrently reading from
session-system-2. Blocking until the other thread is finished using
this session. Please review your code to avoid concurrent use of a
session. java.lang.Exception: Stack trace of concurrent access to
session-system-2
       at org.apache.jackrabbit.core.session.SessionState.perform(SessionState.java:156)
       at org.apache.jackrabbit.core.ItemImpl.perform(ItemImpl.java:91)
       at org.apache.jackrabbit.core.ItemImpl.getPath(ItemImpl.java:376)
       at org.apache.jackrabbit.core.security.user.UserManagerImpl.getAuthorizable(UserManagerImpl.java:737)
       at org.apache.jackrabbit.core.security.user.UserManagerImpl.internalGetAuthorizable(UserManagerImpl.java:797)
       at org.apache.jackrabbit.core.security.user.UserManagerImpl.getAuthorizable(UserManagerImpl.java:401)
       at org.apache.jackrabbit.core.security.authentication.DefaultLoginModule.getPrincipal(DefaultLoginModule.java:88)
       at org.apache.sling.jcr.jackrabbit.server.impl.security.PluggableDefaultLoginModule.getPrincipal(PluggableDefaultLoginModule.java:104)
       at org.apache.jackrabbit.core.security.authentication.AbstractLoginModule.login(AbstractLoginModule.java:313)
       at org.apache.jackrabbit.core.security.authentication.LocalAuthContext.login(LocalAuthContext.java:86)
       at org.apache.jackrabbit.core.RepositoryImpl.login(RepositoryImpl.java:1474)
       at org.apache.sling.jcr.base.AbstractSlingRepository.login(AbstractSlingRepository.java:214)
       at org.apache.sling.jcr.resource.internal.JcrResourceResolverFactoryImpl.getResourceResolverInternal(JcrResourceResolverFactoryImpl.java:291)
       at org.apache.sling.jcr.resource.internal.JcrResourceResolverFactoryImpl.getResourceResolver(JcrResourceResolverFactoryImpl.java:262)
       at org.apache.sling.auth.core.impl.SlingAuthenticator.getResolver(SlingAuthenticator.java:688)
       at org.apache.sling.auth.core.impl.SlingAuthenticator.handleSecurity(SlingAuthenticator.java:429)
       at org.apache.sling.engine.impl.SlingHttpContext.handleSecurity(SlingHttpContext.java:148)
       at org.apache.felix.http.base.internal.context.ServletContextImpl.handleSecurity(ServletContextImpl.java:224)
       at org.apache.felix.http.base.internal.handler.ServletHandler.doHandle(ServletHandler.java:86)
       at org.apache.felix.http.base.internal.handler.ServletHandler.handle(ServletHandler.java:77)
       at org.apache.felix.http.base.internal.dispatch.ServletPipeline.handle(ServletPipeline.java:42)
       at org.apache.felix.http.base.internal.dispatch.InvocationFilterChain.doFilter(InvocationFilterChain.java:49)
       at org.apache.felix.http.base.internal.dispatch.HttpFilterChain.doFilter(HttpFilterChain.java:33)
       at com.etc.pp.custom.server.filter.EnhancePOSTFilter.doFilter(EnhancePOSTFilter.java:114)
       at org.apache.felix.http.base.internal.handler.FilterHandler.doHandle(FilterHandler.java:80)
       at org.apache.felix.http.base.internal.handler.FilterHandler.handle(FilterHandler.java:68)
       at org.apache.felix.http.base.internal.dispatch.InvocationFilterChain.doFilter(InvocationFilterChain.java:47)
       at org.apache.felix.http.base.internal.dispatch.HttpFilterChain.doFilter(HttpFilterChain.java:33)
       at org.apache.felix.http.base.internal.dispatch.FilterPipeline.dispatch(FilterPipeline.java:48)
       at org.apache.felix.http.base.internal.dispatch.Dispatcher.dispatch(Dispatcher.java:39)
       at org.apache.felix.http.base.internal.DispatcherServlet.service(DispatcherServlet.java:55)
       at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
       at org.apache.felix.http.proxy.ProxyServlet.service(ProxyServlet.java:60)
       at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
       at org.apache.sling.launchpad.base.webapp.SlingServletDelegate.service(SlingServletDelegate.java:275)
       at org.apache.sling.launchpad.webapp.SlingServlet.service(SlingServlet.java:130)
       at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
       at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)


Regards,
 Markus