Spring 2.0 schemas not found? And the solution is...

We've experienced a mysterious problem that the Spring 2.0 schemas could not be found when the application context is being created inside an EJB 2.1, using Spring's AbstractStatelessSessionBean.

The problem manifests itself with the following exception:

org.springframework.beans.factory.xml.XmlBeanDefinitionStoreException: Line 18 in XML document from class path resource [springContext.xml] is invalid; nested exception is org.xml.sax.SAXParseException: cvc-elt.1: Cannot find the declaration of element 'beans'.
Caused by:
org.xml.sax.SAXParseException: cvc-elt.1: Cannot find the declaration of element 'beans'.
   at org.apache.xerces.util.ErrorHandlerWrapper.createSAXParseException(Unknown Source)
   at org.apache.xerces.util.ErrorHandlerWrapper.error(Unknown Source)

Normally this is caused by the incorrect XML namespace or schema location declaration at the head of the application context. However, in our case, the declaration was correct:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xmlns:aop="http://www.springframework.org/schema/aop"
  xmlns:jee="http://www.springframework.org/schema/jee"
  xmlns:tx="http://www.springframework.org/schema/tx"
  xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd
       http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.0.xsd
       http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-2.0.xsd
       http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.0.xsd">
...
</bean>

After some research, we found that other people have also experienced this problem.

The cause is that somehow the "META-INF/spring.schemas" and "META-INF/spring.handlers" files packaged in spring.jar could not be found.

What are these two files?

• "spring.schemas" specifies the classpaths of all Spring schemas within the spring.jar. The content of this file is listed below:

http\://www.springframework.org/schema/beans/spring-beans-2.0.xsd=org/springframework/beans/factory/xml/spring-beans-2.0.xsd
http\://www.springframework.org/schema/tool/spring-tool-2.0.xsd=org/springframework/beans/factory/xml/spring-tool-2.0.xsd
http\://www.springframework.org/schema/util/spring-util-2.0.xsd=org/springframework/beans/factory/xml/spring-util-2.0.xsd
http\://www.springframework.org/schema/aop/spring-aop-2.0.xsd=org/springframework/aop/config/spring-aop-2.0.xsd
http\://www.springframework.org/schema/lang/spring-lang-2.0.xsd=org/springframework/scripting/config/spring-lang-2.0.xsd
http\://www.springframework.org/schema/tx/spring-tx-2.0.xsd=org/springframework/transaction/config/spring-tx-2.0.xsd
http\://www.springframework.org/schema/jee/spring-jee-2.0.xsd=org/springframework/ejb/config/spring-jee-2.0.xsd

http\://www.springframework.org/schema/beans/spring-beans.xsd=org/springframework/beans/factory/xml/spring-beans-2.0.xsd
http\://www.springframework.org/schema/tool/spring-tool.xsd=org/springframework/beans/factory/xml/spring-tool-2.0.xsd
http\://www.springframework.org/schema/util/spring-util.xsd=org/springframework/beans/factory/xml/spring-util-2.0.xsd
http\://www.springframework.org/schema/aop/spring-aop.xsd=org/springframework/aop/config/spring-aop-2.0.xsd
http\://www.springframework.org/schema/lang/spring-lang.xsd=org/springframework/scripting/config/spring-lang-2.0.xsd
http\://www.springframework.org/schema/tx/spring-tx.xsd=org/springframework/transaction/config/spring-tx-2.0.xsd
http\://www.springframework.org/schema/jee/spring-jee.xsd=org/springframework/ejb/config/spring-jee-2.0.xsd

• "spring.handlers" specifies the handler class that implements the NamespaceHandler interface for each namespace. The content of this file is listed below:
  

http\://www.springframework.org/schema/util=org.springframework.beans.factory.xml.UtilNamespaceHandler
http\://www.springframework.org/schema/aop=org.springframework.aop.config.AopNamespaceHandler
http\://www.springframework.org/schema/lang=org.springframework.scripting.config.LangNamespaceHandler
http\://www.springframework.org/schema/tx=org.springframework.transaction.config.TxNamespaceHandler
http\://www.springframework.org/schema/jee=org.springframework.ejb.config.JeeNamespaceHandler
http\://www.springframework.org/schema/p=org.springframework.beans.factory.xml.SimplePropertyNamespaceHandler

One raised the topic in Spring's support forum that it was because of no internet access for the application server to access the schemas over the internet. Another post even provided a solution to reference the schemas using classpath prefix directly in the application context configuration files.

However, that's not the root cause and a good solution, because even if the application server can access the schemas over the internet or via classpath prefix, the bootstrap code still cannot access the "spring.handlers" file and would not know how to handle various namespaces other than the default "beans".

In fact, the root cause is that the META-INF directory of a can be blocked when referenced inside an EJB jar.

I tried a few ways to get around this problem, and the final solution I adopted is to extract these two files and put them in the META-INF directory of a JAR file that contains only this directory, and place this JAR file in the lib/ext directory of the application server domain where the application is deployed.

I hope this would help others who may face this problem.