After some reading I found the above null pointer comes when we adding the
context listener BEFORE_START_EVENT occurs. So I changed the event to
STARTING. Now without any error the jaggery context listener added to the
standard context.
But when access the sample tomgery application through URL I got this
error. When I debug this[1] I found appConfigs is null. But could not find
how it happened. Thanks in advance.
*Code : *
protected void service(HttpServletRequest request,
HttpServletResponse response) throws
ServletException, IOException {
JaggeryAppConfigs appConfigs =
JaggeryAppConfigs.getInstance(request.getServletContext());
request.setAttribute("org.apache.catalina.ASYNC_SUPPORTED", true);
AsyncContext asyncCtx = request.startAsync();
asyncCtx.addListener(new JaggeryAsyncListener());
asyncCtx.setTimeout(appConfigs.getServletTimeout());
appConfigs.getServletExecutor().execute(new
JaggeryAsyncRequestProcessor(asyncCtx));
}
*Exception :*
java.lang.NullPointerException
org.jaggeryjs.apps.JaggeryAsyncServlet.service(JaggeryAsyncServlet.java:23)
javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
[1]
https://github.com/ruchiraw/jaggery/blob/master/components/jaggery-core/org.jaggeryjs.apps/src/main/java/org/jaggeryjs/apps/JaggeryAsyncServlet.java
On Sun, Jun 22, 2014 at 5:54 AM, Chamil Jeewantha <[email protected]> wrote:
> Hi Nasmin,
>
> the Null Pointer Exception (NPE) comes from the line
>
> registration.setAsyncSupported(true);
>
> Which means "registration" object is null. The responsible line of
> assigning this variable is the line 25.
>
> ServletRegistration.Dynamic registration = servletContext.addServlet(
> JaggeryAsyncServlet.NAME, JaggeryAsyncServlet.class);
>
> servletContext.addServlet javadoc[1] says,
>
> a ServletRegistration object that may be used to further configure the
> registered servlet, or *null** if this ServletContext already contains a
> complete ServletRegistration for the given **servletName*
>
> For this case you can start debug by two points.
>
> 1. debug JaggeryContextListener
> 2. Debug with tomcat source - servletContext.addServlet method to see why it
> returns null here.
>
>
> [1]
> http://docs.oracle.com/javaee/6/api/javax/servlet/ServletContext.html#addServlet(java.lang.String,
> java.lang.Class)
>
>
>
> On Sat, Jun 21, 2014 at 10:08 PM, Mohamed Nasmin <[email protected]>
> wrote:
>
>> Hi,
>>
>> @Ruchira
>> I will debug the jars that we use in the tomgery app deployment and
>> update with the results.
>>
>> @Dilshan
>> I am using that JaggeryContextListener in a jar which is created by
>> Ruchira. You can find the source code of that jar here[1].
>>
>> @Dakshika
>> With the integration with JSR-223, Jaggery will use Nashorn from JDK8
>> onwards and will fallback to JDK's embeded Rhino version with JDK7 or
>> below. With the above Jaggery core minimisations, a Jaggery app can be even
>> deployed on top of tomcat, subjecting to a WEB-INF directory which contains
>> jaggery core jars and web.xml. For more details please refer this link[2].
>>
>> [1]
>> https://github.com/ruchiraw/jaggery/blob/master/components/jaggery-core/org.jaggeryjs.apps/src/main/java/org/jaggeryjs/apps/JaggeryContextListener.java
>> [2] http://osdir.com/ml/carbon-wso2-architecture/2014-06/msg00000.html
>>
>>
>> On Sat, Jun 21, 2014 at 9:46 PM, Dilshan Edirisuriya <[email protected]>
>> wrote:
>>
>>> Hi,
>>>
>>> Whats there at line 27 of JaggeryContextListener.java? Where can we find
>>> the source for this?
>>>
>>> Regards,
>>>
>>> Dilshan
>>>
>>>
>>> On Sat, Jun 21, 2014 at 1:31 PM, Mohamed Nasmin <[email protected]>
>>> wrote:
>>>
>>>> According to our earlier conversation I am following the below
>>>> progression to accomplish the project. Sorry for the lengthy email.
>>>>
>>>> *Task1. Check whether the app in the tomcat webapps is jaggery app or
>>>> not before it gets deployed/initialized*
>>>>
>>>> I trigger the BEFORE_START_EVENT by configuring the tomcat lifecycle
>>>> listener with context.xml in the tomcat. The context can listen to the
>>>> lifecycle listener by putting jar inside lib folder of tomcat. That jar
>>>> should contain the tomcat listener. Also we need to define that class in
>>>> the context.xml like below (For more details please refer this mail with
>>>> subject Tomcat Lifecycle listener how to.).
>>>>
>>>> <Listener className="org.jaggery.tomcat.listener.TomcatListener" />
>>>>
>>>> When an application is started to deploy BEFORE_START_EVENT will be
>>>> occurred. we check that event get the standard context of that event. To
>>>> find out whether it is a jaggery context or not we identify the
>>>> jaggery.conf in that app folder.
>>>>
>>>> Code :
>>>>
>>>> public void lifecycleEvent(LifecycleEvent event) {
>>>>
>>>> String type = event.getType();
>>>> if (Lifecycle.BEFORE_START_EVENT.equals(type)) {
>>>> LOGGER.log(Level.INFO, "BEFORE START EVENT triggered.");
>>>> Lifecycle source = event.getLifecycle();
>>>>
>>>> if (source instanceof StandardContext) {
>>>>
>>>> StandardContext standardContext = (StandardContext)
>>>> source;
>>>> boolean exists = isJaggeryApp(standardContext);
>>>>
>>>> if (!exists) {
>>>> System.out.println("This is not a Jaggery app");
>>>> } else {
>>>> System.out.println("This is a Jaggery app");
>>>> }
>>>> }
>>>> }
>>>> }
>>>>
>>>> public boolean isJaggeryApp(StandardContext standardContext) {
>>>>
>>>> String contextPath = standardContext.getPath();
>>>> String catalinaPath = System.getProperty("catalina.base");
>>>>
>>>> try{
>>>> File file = new File(catalinaPath + File.separator + "webapps"
>>>> + contextPath + File.separator + "jaggery.conf");
>>>> boolean exists = file.exists();
>>>> }
>>>> catch (Exception e){
>>>> e.printStackTrace();
>>>> }
>>>>
>>>> if (!exists) {
>>>> return false;
>>>> } else {
>>>> return true;
>>>> }
>>>>
>>>> }
>>>>
>>>> Output:
>>>>
>>>> INFO: Deploying web application directory
>>>> /home/nasmin/tomcat/apache-tomcat-7.0.54/webapps/demo3
>>>> Jun 20, 2014 10:25:40 PM org.jaggery.tomcat.listener.TomcatListener
>>>> lifecycleEvent
>>>> INFO: BEFORE START EVENT triggered.
>>>> This is a Jaggery app
>>>>
>>>> *Task2. How to put the jars in the tomcat that apps can see*
>>>>
>>>> After finding the jaggery app in the tomcat we need to assign some jar
>>>> which will be required to get new jaggery engine. So we can put the in a
>>>> directory in the tomcat and we need to mention that in the
>>>> catalina.properties like below.
>>>>
>>>>
>>>> common.loader=${catalina.base}/lib,${catalina.base}/lib/*.jar,${catalina.home}/lib,${catalina.home}/lib/*.jar,${catalina.base}/jaggery/lib,${catalina.base}/jaggery/lib/*.jar,${catalina.home}/jaggery/lib,${catalina.home}/jaggery/lib/*.jar
>>>>
>>>> *Task3. Register a jaggery servlet listener if it is a jaggery app *
>>>>
>>>> Afterwards we need to register our jaggery servlet listener to the
>>>> jaggery app. I did by adding application listener to the jaggery standard
>>>> context and I added application paramaeter which we had in the web.xml.
>>>> Here I got an exception like below. Please advice on this.
>>>>
>>>> Code:
>>>>
>>>>
>>>> standardContext.addApplicationListener("org.jaggeryjs.apps.JaggeryContextListener");
>>>>
>>>> ApplicationParameter applicationParameter = new ApplicationParameter();
>>>> applicationParameter.setName("jaggery.initializer");
>>>> applicationParameter.setValue("server://engines/index.js");
>>>> standardContext.addApplicationParameter(applicationParameter);
>>>>
>>>> ApplicationParameter applicationParameter1 = new ApplicationParameter();
>>>> applicationParameter1.setName("jaggery.development");
>>>> applicationParameter1.setValue("true");
>>>> standardContext.addApplicationParameter(applicationParameter1);
>>>>
>>>> ApplicationParameter applicationParameter2 = new ApplicationParameter();
>>>> applicationParameter2.setName("jaggery.engine.pool.max.active");
>>>> applicationParameter2.setValue("5000");
>>>> standardContext.addApplicationParameter(applicationParameter2);
>>>>
>>>> ApplicationParameter applicationParameter3 = new ApplicationParameter();
>>>> applicationParameter3.setName("jaggery.executor.pool.max");
>>>> applicationParameter3.setValue("5000");
>>>> standardContext.addApplicationParameter(applicationParameter3);
>>>>
>>>> Output:
>>>>
>>>> INFO: Deploying web application directory
>>>> /home/nasmin/tomcat/apache-tomcat-7.0.54/webapps/demo5
>>>> Jun 20, 2014 10:25:39 PM org.jaggery.tomcat.listener.TomcatListener
>>>> lifecycleEvent
>>>> INFO: BEFORE START EVENT triggered.
>>>> This is a Jaggery app
>>>> Jun 20, 2014 10:25:40 PM org.apache.catalina.core.StandardContext
>>>> listenerStart
>>>> SEVERE: Exception sending context initialized event to listener
>>>> instance of class org.jaggeryjs.apps.JaggeryContextListener
>>>> java.lang.NullPointerException
>>>> at
>>>> org.jaggeryjs.apps.JaggeryContextListener.contextInitialized(JaggeryContextListener.java:27)
>>>> at
>>>> org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4973)
>>>> at
>>>> org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5467)
>>>> at
>>>> org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
>>>> at
>>>> org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:901)
>>>> at
>>>> org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877)
>>>> at
>>>> org.apache.catalina.core.StandardHost.addChild(StandardHost.java:632)
>>>> at
>>>> org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1247)
>>>> at
>>>> org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1898)
>>>> at
>>>> java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
>>>> at java.util.concurrent.FutureTask.run(FutureTask.java:262)
>>>> at
>>>> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
>>>> at
>>>> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
>>>> at java.lang.Thread.run(Thread.java:744)
>>>>
>>>> Jun 20, 2014 10:25:40 PM org.apache.catalina.core.StandardContext
>>>> startInternal
>>>> SEVERE: Error listenerStart
>>>>
>>>> I attached the tomcat directory structure for the jaggery app with this
>>>> email. Also we have a remaining task that we need put context parameters in
>>>> a separate property file and make it available for the app deployment. Here
>>>> I hard coded those parameters. Please advice on this issue.
>>>>
>>>> Thanks in advance.
>>>>
>>>> _______________________________________________
>>>> Dev mailing list
>>>> [email protected]
>>>> http://wso2.org/cgi-bin/mailman/listinfo/dev
>>>>
>>>>
>>>
>>>
>>> --
>>> Dilshan Edirisuriya
>>> Senior Software Engineer - WSO2
>>> Mob: + 94 777878905
>>> http://wso2.com/
>>>
>>
>>
>> _______________________________________________
>> Dev mailing list
>> [email protected]
>> http://wso2.org/cgi-bin/mailman/listinfo/dev
>>
>>
>
>
> --
> K.D. Chamil Jeewantha
> Associate Technical Lead
> WSO2, Inc.; http://wso2.com
> Mobile: +94716813892
>
>
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