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Asynchronous request dispatcher (ARD) servlets might not work with servlet caching enabled.

Troubleshooting


Problem

An SRVE0068E message similar to the following one occurs when you use servlet caching with asynchronous request dispatcher (ARD): [8/4/16 14:37:29:051 EDT] 000000f6 ServletWrappe E com.ibm.ws.webcontainer.servlet.ServletWrapper service SRVE0068E: An exception was thrown by one of the service methods of the servlet [xxxxx] in application [xxxx]. Exception created : [java.lang.IllegalStateException: NULL parent fragment composer for an ASYNC Include.

Cause

WebSphere Application Server Version 9.0 introduced a performance enhancement to servlet caching. Prior to Version 9.0, all requests flowed through servlet caching when servlet caching was enabled. In Version 9.0, only requests that flow to a web module with a cachespec.xml file flow through servlet caching.

Resolving The Problem

If an application is using ARD or relying on all requests to flow through servlet caching, then a caching policy must exist in a cachespec.xml file for the request that needs to flow through servlet caching. For example, when an ARD child exists in a web module that contains a cachespec.xml file, then the child fragment flows through servlet caching. If the parent is not in a web module with a cachespec.xml file, then servlet caching never sees the parent fragment. As a result, when the child fragment flows through servlet caching, an exception is created because servlet caching does not know the parent fragment.

To resolve the exception, place a cachespec.xml file in the WEB-INF directory of the web module of the parent fragment. This placement ensures that the parent fragment flows through servlet caching.

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Document Information

Modified date:
15 June 2018

UID

swg21989663