500 Servlet Exception

java.lang.ClassCastException
at com.rolia.ourWriting.ArticleFile.getContent(ArticleFile.java:41)
at com.rolia.ourWriting.Article.<init>(Article.java:29)
at _jsp._ow_0modifyArticle__jsp._jspService(_ow_0modifyArticle__jsp.java:214)
at com.caucho.jsp.JavaPage.service(JavaPage.java:61)
at com.caucho.jsp.Page.pageservice(Page.java:569)
at com.caucho.server.dispatch.PageFilterChain.doFilter(PageFilterChain.java:149)
at com.caucho.server.webapp.WebAppFilterChain.doFilter(WebAppFilterChain.java:163)
at com.caucho.server.dispatch.ServletInvocation.service(ServletInvocation.java:208)
at com.caucho.server.hmux.HmuxRequest.handleRequest(HmuxRequest.java:386)
at com.caucho.server.port.TcpConnection.run(TcpConnection.java:332)
at com.caucho.util.ThreadPool.runTasks(ThreadPool.java:457)
at com.caucho.util.ThreadPool.run(ThreadPool.java:398)
at java.lang.Thread.run(Thread.java:534)