strange "String index out of range: 0" error

I have a huge application and at some point, when a redirect is involved i received this strange error:

Caused by java.lang.StringIndexOutOfBoundsException with message: "String index out of range: 0"    
java.lang.String.charAt(String.java:687)
com.sun.faces.application.ViewHandlerImpl.getActionURL(ViewHandlerImpl.java:652)
org.jboss.seam.jsf.SeamViewHandler.getActionURL(SeamViewHandler.java:74)
com.sun.facelets.FaceletViewHandler.getActionURL(FaceletViewHandler.java:803)
org.ajax4jsf.application.ViewHandlerWrapper.getActionURL(ViewHandlerWrapper.java:86)
org.jboss.seam.ui.util.ViewUrlBuilder.<init>(ViewUrlBuilder.java:25)
org.jboss.seam.ui.component.UISeamCommandBase.getUrl(UISeamCommandBase.java:48)
org.jboss.seam.ui.renderkit.LinkRendererBase.doEncodeBegin(LinkRendererBase.java:26)
org.jboss.seam.ui.util.cdk.RendererBase.encodeBegin(RendererBase.java:79)
javax.faces.component.UIComponentBase.encodeBegin(UIComponentBase.java:813)
javax.faces.component.UIComponent.encodeAll(UIComponent.java:934)
javax.faces.component.UIComponent.encodeAll(UIComponent.java:942)
javax.faces.component.UIComponent.encodeAll(UIComponent.java:942)
com.sun.facelets.FaceletViewHandler.renderView(FaceletViewHandler.java:592)
org.ajax4jsf.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:100)
org.ajax4jsf.application.AjaxViewHandler.renderView(AjaxViewHandler.java:176)
com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:109)
com.sun.faces.lifecycle.Phase.doPhase(Phase.java:100)
com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139)
javax.faces.webapp.FacesServlet.service(FacesServlet.java:266)
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:83)
org.jboss.seam.web.RewriteFilter.doFilter(RewriteFilter.java:63)
org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
org.jboss.seam.web.IdentityFilter.doFilter(IdentityFilter.java:40)
org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
org.jboss.seam.web.MultipartFilter.doFilter(MultipartFilter.java:90)
org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
org.jboss.seam.web.ExceptionFilter.doFilter(ExceptionFilter.java:64)
org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
org.jboss.seam.web.RedirectFilter.doFilter(RedirectFilter.java:45)
org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:73)
org.ajax4jsf.webapp.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:178)
org.ajax4jsf.webapp.BaseFilter.handleRequest(BaseFilter.java:290)
org.ajax4jsf.webapp.BaseFilter.processUploadsAndHandleRequest(BaseFilter.java:388)
org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:515)
org.jboss.seam.web.Ajax4jsfFilter.doFilter(Ajax4jsfFilter.java:56)
org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
org.jboss.seam.web.LoggingFilter.doFilter(LoggingFilter.java:60)
org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
org.jboss.seam.web.HotDeployFilter.doFilter(HotDeployFilter.java:53)
org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
org.jboss.seam.servlet.SeamFilter.doFilter(SeamFilter.java:158)
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230)
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:182)
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:432)
org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:84)
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:157)
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:262)
org.apache.coyot开发者_如何学JAVAe.http11.Http11Processor.process(Http11Processor.java:844)
org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:446)
java.lang.Thread.run(Thread.java:619)

I've spent two hours debugging and so on, but did not find any clue... It's just weird because the error log does not tell something clear...(which string, which property is involved etc).

Does anyone can guess something more from the stacktrace?

Thanks.

---

Let's check what ViewHandlerImpl#getActionURL() does (Mojarra is just open source). Here's is a summarized/stripped extract of the method as it is in Mojarra 2.0.2:

public String getActionURL(FacesContext context, String viewId) {
    if (context == null) throw new NullPointerException();
    if (viewId == null) throw new NullPointerException();
    if (viewId.charAt(0) != '/') throw new IllegalArgumentException();
    // ...

In other words, the passed-in viewId is an empty string instead of null or / or the normal path. The Mojarra viewhandler didn't expect it at all, hence this runtime exception. It can be a bug in the view handler of Mojarra that it should handle empty strings as well, but it can also be a bug in the view handler of either Ajax4jsf, Facelets or Seam that it should never pass an empty string through up. It can also be a bug in your own code that you're actually passing an empty string as view ID.

If the problem isn't in your code, then I would start with upgrading what can be upgraded to see if it resolves the problem. Maybe it was already reported before as a bug and fixed in a newer release. If that doesn't help, I would check the classpath for duplicate JAR files of different versions which might have collided with each other.

---

My first guess would be that you have an empty string "", of which you are trying to get the first character (at index 0)

---

In my case i ve solved the issure reviewing all my page´s ids. I was rendering a facelet in two cases and in one of those there was a reference to an id that not existed.

In my jsf facelet: The reference to #{finishBtn} did not exists because it was not passed from the page which called this.

<ui:composition>
    ......
    ....
     <a4j:commandButton title="#{i18n.editar_er_tip}"
                        image="/images/edit.png" style="width:16px;height:16px" reRender="entregablesTable,#{finishBtn},entregableBotton"
                        action="#{actionBean[editMethod]}"
                        onclick="Richfaces.showModalPanel('waitPanel')"
                        oncomplete="Richfaces.hideModalPanel('waitPanel');Richfaces.showModalPanel('entregableBotton')">
    </a4j:commandButton>
    ....
    ..
</ui:composition>

I have solved with a previous evaluation

<c:if test="${empty finishBtn}">
        <c:set var="finishBtn" value="editButton" />
</c:if>