Learn. Develop. Share.

Problem #1:
You get a StackOverFlowError, and the log looks like this:

2011-06-14 16:42:26,939 ERROR [org.jboss.seam.exception.Exceptions] (http-localhost%2F127.0.0.1-8080-4) handled and logged exception: javax.servlet.ServletException: Servlet execution threw an exception
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:341) [:6.0.0.Final]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:242) [:6.0.0.Final]
	at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:83) [:2.2.2.Final]
	at org.jboss.seam.web.IdentityFilter.doFilter(IdentityFilter.java:40) [:2.2.2.Final]
	at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) [:2.2.2.Final]
	at org.jboss.seam.web.MultipartFilter.doFilter(MultipartFilter.java:90) [:2.2.2.Final]
	at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) [:2.2.2.Final]
	at org.jboss.seam.web.ExceptionFilter.doFilter(ExceptionFilter.java:64) [:2.2.2.Final]
	at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) [:2.2.2.Final]
	at org.jboss.seam.web.RedirectFilter.doFilter(RedirectFilter.java:45) [:2.2.2.Final]
	at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) [:2.2.2.Final]
	at org.ajax4jsf.webapp.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:206) [:3.3.3.Final]
	at org.ajax4jsf.webapp.BaseFilter.handleRequest(BaseFilter.java:290) [:3.3.3.Final]
	at org.ajax4jsf.webapp.BaseFilter.processUploadsAndHandleRequest(BaseFilter.java:388) [:3.3.3.Final]
	at org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:515) [:3.3.3.Final]
	at org.jboss.seam.web.Ajax4jsfFilter.doFilter(Ajax4jsfFilter.java:56) [:2.2.2.Final]
	at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) [:2.2.2.Final]
	at org.jboss.seam.web.LoggingFilter.doFilter(LoggingFilter.java:60) [:2.2.2.Final]
	at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) [:2.2.2.Final]
	at org.jboss.seam.servlet.SeamFilter.doFilter(SeamFilter.java:158) [:2.2.2.Final]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:274) [:6.0.0.Final]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:242) [:6.0.0.Final]
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:275) [:6.0.0.Final]
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191) [:6.0.0.Final]
	at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:181) [:6.0.0.Final]
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501) [:6.0.0.Final]
	at org.jboss.modcluster.catalina.CatalinaContext$RequestListenerValve.event(CatalinaContext.java:285) [:1.1.0.Final]
	at org.jboss.modcluster.catalina.CatalinaContext$RequestListenerValve.invoke(CatalinaContext.java:261) [:1.1.0.Final]
	at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:88) [:6.0.0.Final]
	at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.invoke(SecurityContextEstablishmentValve.java:100) [:6.0.0.Final]
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) [:6.0.0.Final]
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) [:6.0.0.Final]
	at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:158) [:6.0.0.Final]
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) [:6.0.0.Final]
	at org.jboss.web.tomcat.service.request.ActiveRequestResponseCacheValve.invoke(ActiveRequestResponseCacheValve.java:53) [:6.0.0.Final]
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:362) [:6.0.0.Final]
	at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:877) [:6.0.0.Final]
	at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:654) [:6.0.0.Final]
	at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:951) [:6.0.0.Final]
	at java.lang.Thread.run(Thread.java:662) [:1.6.0_24]
Caused by: java.lang.StackOverflowError
	at org.jboss.logmanager.Logger.log(Logger.java:597) [jboss-logmanager.jar:1.2.0.CR9]
	at org.jboss.logmanager.Logger.log(Logger.java:612) [jboss-logmanager.jar:1.2.0.CR9]
	at org.jboss.logmanager.log4j.BridgeLogger.error(BridgeLogger.java:72) [:6.0.0.Final]
	at org.jboss.seam.interop.jul.Log4JConversionFilter.logWithThrowable(Log4JConversionFilter.java:86) [:2.2.2.Final]
	at org.jboss.seam.interop.jul.Log4JConversionFilter.isLoggable(Log4JConversionFilter.java:68) [:2.2.2.Final]
	at org.jboss.logmanager.Logger.logRaw(Logger.java:640) [jboss-logmanager.jar:1.2.0.CR9]
	at org.jboss.logmanager.Logger.log(Logger.java:600) [jboss-logmanager.jar:1.2.0.CR9]
	at org.jboss.logmanager.Logger.log(Logger.java:612) [jboss-logmanager.jar:1.2.0.CR9]
	at org.jboss.logmanager.log4j.BridgeLogger.error(BridgeLogger.java:72) [:6.0.0.Final]
	at org.jboss.seam.interop.jul.Log4JConversionFilter.logWithThrowable(Log4JConversionFilter.java:86) [:2.2.2.Final]
	at org.jboss.seam.interop.jul.Log4JConversionFilter.isLoggable(Log4JConversionFilter.java:68) [:2.2.2.Final]
	at org.jboss.logmanager.Logger.logRaw(Logger.java:640) [jboss-logmanager.jar:1.2.0.CR9]

Solution:
jboss-seam-jul-X.Y.X.WWWWW.jar should not be included in WEB-INF/lib
Modify the parent project pom.xml:
Before:

<dependency>
	<groupId>org.jboss.seam</groupId>
	<artifactId>jboss-seam-ui</artifactId>
	<version>${seam.version}</version>
	<exclusions>
		<exclusion>
			<artifactId>servlet-api</artifactId>
			<groupId>javax.servlet</groupId>
		</exclusion>
	</exclusions>
</dependency>

After:

<dependency>
	<groupId>org.jboss.seam</groupId>
	<artifactId>jboss-seam-ui</artifactId>
	<version>${seam.version}</version>
	<exclusions>
		<exclusion>
			<artifactId>servlet-api</artifactId>
			<groupId>javax.servlet</groupId>
		</exclusion>
		<exclusion>
			<groupId>org.jboss.seam</groupId>
			<artifactId>jboss-seam-jul</artifactId>
		</exclusion>
	</exclusions>
</dependency>

Tip:
.xhtml files generated automatically by seam-gen and JBoss Tools contain some errors.

Change the tag attribute
from:
template="layout/template.xhtml"
to:
template="/layout/template.xhtml"

Change the tag attribute
from:
template="layout/edit.xhtml"
to:
template="/layout/edit.xhtml"

This shrewdness will prevent annoying errors if you decide to move pages between folders.