ClassCastException Thrown When Getting X509Certificate in Jetty-7.1.6.v20100715 - classloader

Question

The filter I wrote threw ClassCastException
[Ljava.security.cert.X509Certificate; cannot be cast to java.security.cert.X509Certificate
when I tried to cast an Object extracted from the ServletRequest attribute, i.e.
public void doFilter(ServletRequest req, ServletResponse res, FilterChain filterChain) throws
IOException, ServletException
{
X509Certificate cert = (X509Certificate) req.getAttribute("javax.servlet.request.X509Certificate");
System.out.println("cert dn " + cert.getSubjectDN().toString());
filterChain.doFilter(req, res);
}
As I dug deeper I understood that exception like this was most probably caused by different classloaders though they are of same class type. How do I resolve this?
Thanks
I used the following Spring 3 configurarion to load Jetty 7 piecemeal
<bean class="org.eclipse.jetty.server.Server"
init-method="start" destroy-method="stop">
<property name="connectors">
<list>
<bean id="SSLConnector" class="org.eclipse.jetty.server.ssl.SslSocketConnector">
<property name="port" value="8553"/>
<property name="maxIdleTime" value="3600000"/>
<property name="soLingerTime" value="-1"/>
<property name="needClientAuth" value="true"/>
<property name="sslContext">
<ref bean="sslContext"/>
</property>
</bean>
</list>
</property>
<property name="handler">
<bean name="contexts" class="org.eclipse.jetty.server.handler.ContextHandlerCollection">
<property name="handlers">
<list>
<bean class="org.eclipse.jetty.servlet.ServletContextHandler">
<property name="contextPath">
<value>/caas</value>
</property>
<property name="resourceBase" value="src/main/secure_webapp"/>
<property name="sessionHandler">
<bean class="org.eclipse.jetty.server.session.SessionHandler"/>
</property>
<property name="servletHandler">
<bean class="org.eclipse.jetty.servlet.ServletHandler">
<property name="filters">
<list>
<bean class="org.eclipse.jetty.servlet.FilterHolder">
<property name="name" value="myfilter"/>
<property name="filter">
<bean class="com.acme.MyFilter"/>
</property>
</bean>
</list>
</property>
<property name="filterMappings">
<list>
<bean class="org.eclipse.jetty.servlet.FilterMapping">
<property name="pathSpec">
<value>/*</value>
</property>
<property name="filterName"
value="myfilter"/>
</bean>
</list>
</property>
<property name="servlets">
<list>
<bean class="org.eclipse.jetty.servlet.ServletHolder">
<property name="name" value="default"/>
<property name="servlet">
<bean class="org.eclipse.jetty.servlet.DefaultServlet"/>
</property>
</bean>
</list>
</property>
<property name="servletMappings">
<list>
<bean class="org.eclipse.jetty.servlet.ServletMapping">
<property name="pathSpecs">
<list>
<value>/</value>
</list>
</property>
<property name="servletName" value="default"/>
</bean>
</list>
</property>
</bean>
</property>
</bean>
</list>
</property>
</bean>
</property>
</bean>

Answer 1

I don't think it's a duplicate class problem in this case, because X509Certificate is contained in the core JRE libraries. There is, afaik, no other library which provides this abstract class.
I think the problem is the getAttribute() returns an array of X509Certificate objects, whereas you cast it down to a single object. The beginning [L of the ClassCastException message indicates that the object returned is an array.
Try casting to an array of certificates:
X509Certificate[] cert = (X509Certificate[])
req.getAttribute("javax.servlet.request.X509Certificate");
Also, i think that you should retrieve the object from getAttribute() and use instanceof checks to see whether it contains the desired types and maybe handle them differently.