Instability when running two Vaadin portlets in portal?

General
1

Hi,
We configured our Liferay to handle multiple Vaadin portlets according to these directions:

http://www.liferay.com/community/wiki/-/wiki/Main/Developing%20Vaadin%20Applications%20as%20Liferay%20Portlets/pop_up#section-Developing+Vaadin+Applications+as+Liferay+Portlets-PrepareYourLiferay5.2ToHandleMultipleVaadinPortlets

However, occasionally the system gives the following exception for the other portlet, and the portal shows red message of malfuction in portlet (the other portlet works all the time):

09:39:19,688 ERROR [jsp:165]
java.lang.NullPointerException
at com.vaadin.terminal.gwt.server.AbstractWebApplicationContext.endTransaction(AbstractWebApplicatntext.java:86)
at com.vaadin.terminal.gwt.server.AbstractApplicationServlet.service(AbstractApplicationServlet.ja4)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:29
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:630)
at org.apache.catalina.core.ApplicationDispatcher.doInclude(ApplicationDispatcher.java:535)
at org.apache.catalina.core.ApplicationDispatcher.include(ApplicationDispatcher.java:472)
at com.liferay.portlet.InvokerPortletImpl.invoke(InvokerPortletImpl.java:618)
at com.liferay.portlet.InvokerPortletImpl.invokeRender(InvokerPortletImpl.java:700)
at com.liferay.portlet.InvokerPortletImpl.render(InvokerPortletImpl.java:419)
at org.apache.jsp.html.portal.render_005fportlet_jsp._jspService(render_005fportlet_jsp.java:1467)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:374)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

Have you faced anything like this? Thanks.

Liferay 5.2.3 / Vaadin 6.3.3

  • L -
2

The first few lines of the stack trace seem to be corrupted, so I cannot be certain of the line numbers and if there is something missing. However, the only way I see there could be a NPE from AbstractWebApplicationContext.endTransaction() is if a TransactionListener is null.

Do you add your own transaction listeners? Are you sure they are not null? Does your TransactionListener try to manipulate the list of TransactionListeners?

3

AbstractWebApplicationContext .java

71 synchronized (listeners) {
72 for (TransactionListener listener : listeners) {
73 try {
74 listener.transactionEnd(application, request);
75 } catch (final RuntimeException t) {
76 if (exceptions == null) {
77 exceptions = new LinkedList();
78 }
79 exceptions.add(t);
80 }

this gives NPE as far as our research tells us. The problem might be in our way to integrate with Spring.

… trying to find the solution.

Thanks for tip - I will write down the resolution when found… hope we will…

  • L -
4

I added a null check when registering a transaction listener and a note in the javadoc in
ticket 5127
 .