ATG taglibs on OSGI problems

Question

We're currently creating an app that needs ATG taglibs on SLING/OSGI, we have created a bundle with these taglibs and uploaded it, of course these taglibs call ATG classes, so we are including them in the bootdelegation, using sling.properties file.

sling.bootdelegation.simple=atg.nucleus sling.bootdelegation.class.atg.nucleus.Nucleus=atg.appassembly, \ atg.appassembly.ant, \ atg.appassembly.progress, \ atg.appassembly.util, \ ...ETC...

First we got this error:

org.apache.sling.api.scripting.ScriptEvaluationException: atg/taglib/dspjsp/ImportBeanTag at org.apache.sling.scripting.core.impl.DefaultSlingScript.call(DefaultSlingScript.java:163) at org.apache.sling.scripting.core.impl.DefaultSlingScript.eval(DefaultSlingScript.java:107) at org.apache.sling.scripting.core.impl.DefaultSlingScript.service(DefaultSlingScript.java:226) at org.apache.sling.engine.impl.request.RequestData.service(RequestData.java:465)

....

.... Caused by: java.lang.NoClassDefFoundError: atg/taglib/dspjsp/ImportBeanTag at org.apache.jsp.apps.mygeometrixx.components.contenpage.center_jsp._jspx_meth_dsp_005fimportbean_005f0(center_jsp.java:177) at org.apache.jsp.apps.mygeometrixx.components.contenpage.center_jsp._jspService(center_jsp.java:154) at org.apache.sling.scripting.jsp.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) at javax.servlet.http.HttpServlet.service(HttpServlet.java:810) at

So we added atg.taglib.dspjsp to the packages to be added in bootdelegation sling.properties file.

Then we got this error:

org.apache.sling.api.scripting.ScriptEvaluationException: atg.taglib.dspjsp.ImportBeanTag at org.apache.sling.scripting.core.impl.DefaultSlingScript.call(DefaultSlingScript.java:163) at org.apache.sling.scripting.core.impl.DefaultSlingScript.eval(DefaultSlingScript.java:107) at org.apache.sling.scripting.core.impl.DefaultSlingScript.service(DefaultSlingScript.java:226) at org.apache.sling.engine.impl.request.RequestData.service(RequestData.java:465) ...

Caused by: java.lang.ClassCastException: atg.taglib.dspjsp.ImportBeanTag at org.apache.sling.scripting.jsp.jasper.runtime.TagHandlerPool.get(TagHandlerPool.java:125) at org.apache.jsp.apps.mygeometrixx.components.contenpage.center_jsp._jspx_meth_dsp_005fimportbean_005f0(center_jsp.java:177) at org.apache.jsp.apps.mygeometrixx.components.contenpage.center_jsp._jspService(center_jsp.java:154) at org.apache.sling.scripting.jsp.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)

All this is running on JBOSS.

Is there a way to avoid this class conflict that is causing the cast exception?

Answer 1

The class cast exception is usually a sign that that class is being made available in two different places (in your case probably via bootdelegation and maybe via a bundle that exports this class). That's what I would investigate first.

Also, to make things more explicit, I would in general advise you to not use boot delegation but instead export these packages explicitly through the system bundle. That way at least you can better debug where classes come from and how things are "wired" by the OSGi resolver.