【转】java.lang.LinkageError: loader constraint violation: when resolving interface method异常

严重: Servlet.service() for servlet jsp threw exception
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 avax/el/ExpressionFactory; used in the signature
at org.apache.jsp.index_jsp._jspInit(index_jsp.java:22)
at org.apache.jasper.runtime.HttpJspBase.init(HttpJspBase.java:52)
at org.apache.jasper.servlet.JspServletWrapper.getServlet(JspServletWrapper.java:164)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:340)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:723)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.shiro.web.servlet.ProxiedFilterChain.doFilter(ProxiedFilterChain.java:61)
at org.apache.shiro.web.servlet.AdviceFilter.executeChain(AdviceFilter.java:108)
at org.apache.shiro.web.servlet.AdviceFilter.doFilterInternal(AdviceFilter.java:137)
at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125)
at org.apache.shiro.web.servlet.ProxiedFilterChain.doFilter(ProxiedFilterChain.java:66)
at org.apache.shiro.web.servlet.AbstractShiroFilter.executeChain(AbstractShiroFilter.java:449)
at org.apache.shiro.web.servlet.AbstractShiroFilter1.call(AbstractShiroFilter.java:365)atorg.apache.shiro.subject.support.SubjectCallable.doCall(SubjectCallable.java:90)atorg.apache.shiro.subject.support.SubjectCallable.call(SubjectCallable.java:83)atorg.apache.shiro.subject.support.DelegatingSubject.execute(DelegatingSubject.java:383)atorg.apache.shiro.web.servlet.AbstractShiroFilter.doFilterInternal(AbstractShiroFilter.java:362)atorg.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125)atorg.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346)atorg.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:259)atorg.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)atorg.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)atch.qos.logback.classic.helpers.MDCInsertingServletFilter.doFilter(MDCInsertingServletFilter.java:51)atorg.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)atorg.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)atcom.jpx.component.config.filter.XssFilter.doFilter(XssFilter.java:129)atorg.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)atorg.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)atorg.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)atorg.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)atorg.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)atorg.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)atorg.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)atorg.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)atorg.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcessor.java:879)atorg.apache.coyote.http11.Http11AprProtocolHttp11ConnectionHandler.process(Http11AprProtocol.java:617)
at org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:1778)
at java.lang.Thread.run(Thread.java:745)

解决方案：

jbpm4 在tomcat6 下面ssh2 这个错误！
原因是项目中WEB-INF\lib中的三个jar包(juel.jar, juel-engine.jar, juel-impl.jar)和tomcat6下lib中jar包(el-api.jar)冲突
解决方法：
方法一：换成tomcat5.5 一点问题也没有了
方法二：将juel.jar, juel-engine.jar, juel-impl.jar这三个包复制到tomcat6下lib中，并删除原来的el-api.jar，
切记要把WEB-INF\lib中的juel.jar, juel-engine.jar, juel-impl.jar删除。不然还是要冲突。