javax.servlet.ServletException: java.lang.LinkageError: loader constraint violation: when resolving interface method "javax.servlet.jsp.JspApplicationContext.getExpressionFactory()Ljavax/el/ExpressionFactory;" the class loader (instance of org/apache/jasper/servlet/JasperLoader) of the current class, org/apache/jsp/index_jsp, and the class loader (instance of org/apache/catalina/loader/StandardClassLoader) for resolved class, javax/servlet/jsp/JspApplicationContext, have different Class objects for the type javax/el/ExpressionFactory used in the signature org.apache.jasper.servlet.JspServlet.service(JspServlet.java:268)
……
該異常爲jar包衝突
使用jBPM4.4時如果使用apache-tomcat-6.0.35發佈工程會出現該異常
解決方法：1.更換tomcat的其他版本
2.把jBPM4.4的依賴包（juel-api.jar，juel-engine.jar，juel-impl.jar）替換掉apache-tomcat-6.0.35\lib下的（el-api.jar），並在工程中刪除（juel-api.jar， juel-engine.jar，juel-impl.jar）這三個包