求大神！EJB3.0 JBoss
java.lang.ClassCastException: $Proxy75 cannot be cast to com.jov.project.dao.BookDao
org.apache.jsp.index_jsp._jspService(index_jsp.java:242)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:373)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:336)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
这是什么问题？
望大神解决··

------解决方案--------------------
代理类在转换com.jov.project.dao.BookDao
时，转换不了，‘
你的ejb用了接口没？
怎么定义ejb的