Difference between calling back bean method using parenthesis and without parenthesis in jsf? [duplicate]

Question

what is the difference between

  <h:commandLink actionListener="#{serviceProviderBean.method}" value="Save" />

and

 <h:commandLink actionListener="#{serviceProviderBean.method()}" value="Save" />

is both invoke same method or any error in above code

Answer 1

Second will not work under tomcat6, it will work with tomcat7/jSF2