javax.el.ELException: Cannot convert output of type class java.lang.String

JSF

Piyush

Asked on January 23, 2015

Hi,

I am creating JSF composite component demo application. Need help to resolve below exception.

javax.el.ELException: Cannot convert output of type class java.lang.String to class javax.el.MethodExpression

org.apache.el.lang.ELSupport.coerceToType(ELSupport.java:419)

org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:186)

com.sun.faces.facelets.el.ContextualCompositeValueExpression.getValue(Unknown Source)

com.sun.faces.facelets.el.TagValueExpression.getValue(Unknown Source)

com.sun.faces.facelets.tag.TagAttributeImpl$AttributeLookupMethodExpression.invoke(Unknown Source)

javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(Unknown Source)

com.sun.faces.application.ActionListenerImpl.processAction(Unknown Source)

javax.faces.component.UICommand.broadcast(Unknown Source)

javax.faces.component.UIViewRoot.broadcastEvents(Unknown Source)

javax.faces.component.UIViewRoot.processApplication(Unknown Source)

com.sun.faces.lifecycle.InvokeApplicationPhase.execute(Unknown Source)

com.sun.faces.lifecycle.Phase.doPhase(Unknown Source)

com.sun.faces.lifecycle.LifecycleImpl.execute(Unknown Source)

javax.faces.webapp.FacesServlet.service(Unknown Source)

org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

Jeet

Replied on January 23, 2015

Please explain what are you creating.

Piyush

Replied on January 23, 2015

I am creating a composite component in JSF and creating command button as below.

<composite:interface>

--------------------

---------------------

<composite:attribute name="submitButtonAction" />

</composite:interface>

<composite:implementation>

-----------------------

----------------------

<h:commandButton value="#{cc.attrs.submitButtonLabel}" action="#{cc.attrs.submitButtonAction}"/>

</composite:implementation>

Jeet

Replied on January 23, 2015

You have not defined <b>method-signature</b> in <composite:attribute name="submitButtonAction" />

define it as

<composite:attribute name="submitButtonAction" method-signature="java.lang.String anyMethod()" />
in <composite:interface>