Displaying Error Msg in Jsp when Content List or Article is empty or null

Displaying Error Msg in Jsp when Content List or Article is empty or null

1.           

<!—This tag will  display the journal article with in the Template mentioned à

if(articleDisplay!=null){

            %>

<div>

      <liferay-ui:journal-article templateId="SAMPLE_TEMPLATE_ID"

                  articleId="<%= articleDisplay.getArticleId() %>"

                  groupId="<%= groupId %>" />

</div>

<%   

}else{

      %>   

      <!—This line will show a error when there is no journal article available with the give ID à

<div class="portlet-msg-error">

 No Article exists with the articleId=<%= articleId%> .

</div>     

      <%   

            }