java.lang.NoClassDefFoundError: Could not initialize class com.opensymphony.module.sitemesh.taglib.decorator.BodyTag        sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)        sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)        sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)        java.lang.reflect.Constructor.newInstance(Constructor.java:423)        java.lang.Class.newInstance(Class.java:442)        org.apache.jasper.runtime.TagHandlerPool.get(TagHandlerPool.java:120)        org.apache.jsp.WEB_002dINF.layouts.layout_jsp._jspx_meth_decorator_005fbody_005f0(layout_jsp.java:114)        org.apache.jsp.WEB_002dINF.layouts.layout_jsp._jspService(layout_jsp.java:83)        org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)        javax.servlet.http.HttpServlet.service(HttpServlet.java:728)        org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)        org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)        org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)        javax.servlet.http.HttpServlet.service(HttpServlet.java:728)        com.opensymphony.sitemesh.compatability.OldDecorator2NewDecorator.render(OldDecorator2NewDecorator.java:46)        com.opensymphony.sitemesh.webapp.decorator.BaseWebAppDecorator.render(BaseWebAppDecorator.java:33)        com.opensymphony.sitemesh.webapp.SiteMeshFilter.doFilter(SiteMeshFilter.java:85)        org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:96)
配置什么的都没错，这是什么原因。。。。

java.lang.NoClassDefFoundError: Could not initialize class com.opensymphony.module.sitemesh.taglib.decorator.BodyTag        sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)        sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)        sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)        java.lang.reflect.Constructor.newInstance(Constructor.java:423)        java.lang.Class.newInstance(Class.java:442)        org.apache.jasper.runtime.TagHandlerPool.get(TagHandlerPool.java:120)        org.apache.jsp.WEB_002dINF.layouts.layout_jsp._jspx_meth_decorator_005fbody_005f0(layout_jsp.java:114)        org.apache.jsp.WEB_002dINF.layouts.layout_jsp._jspService(layout_jsp.java:83)        org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)        javax.servlet.http.HttpServlet.service(HttpServlet.java:728)        org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)        org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)        org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)        javax.servlet.http.HttpServlet.service(HttpServlet.java:728)        com.opensymphony.sitemesh.compatability.OldDecorator2NewDecorator.render(OldDecorator2NewDecorator.java:46)        com.opensymphony.sitemesh.webapp.decorator.BaseWebAppDecorator.render(BaseWebAppDecorator.java:33)        com.opensymphony.sitemesh.webapp.SiteMeshFilter.doFilter(SiteMeshFilter.java:85)        org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:96)
配置什么的都没错，这是什么原因。。。。