org.apache.jasper.JasperException: cannot assign instance of net.sf.jasperreports.engine.base.JRBas

出现  org.apache.jasper.JasperException  异常

代码如下:
File reportFile = new File(application.getRealPath("/reports/IT Report1.jasper"));
  Map parameters = new HashMap();
parameters.put("", "");
 
byte[] bytes=JasperRunManager.runReportToPdf(reportFile.getPath(),parameters,Conn);

response.setContentType("application/pdf");
response.setContentLength(bytes.length);
ServletOutputStream ouputStream=response.getOutputStream();
ouputStream.write(bytes,0,bytes.length);
ouputStream.flush();
ouputStream.close();

报出的错误为:
Type:Exception report
message:
description:The server encountered an internal error () that prevented it from fulfilling this request.
exception: 
  org.apache.jasper.JasperException: cannot assign instance of  net.sf.jasperreports.engine.base.JRBaseStaticText to field net.sf.jasperreports.engine.base.JRBaseLineBox.boxContainer of type net.sf.jasperreports.engine.JRBoxContainer in instance of net.sf.jasperreports.engine.base.JRBaseLineBox
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:207)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:240)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:187)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:809)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:200)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:146)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:209)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:596)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:433)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:948)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:144)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:596)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:433)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:948)
at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2358)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:133)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:596)
at org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.java:118)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:594)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:116)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:594)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:433)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:948)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:127)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:596)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:433)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:948)
at org.apache.coyote.tomcat4.CoyoteAdapter.service(CoyoteAdapter.java:152)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:799)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:705)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:577)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
at java.lang.Thread.run(Thread.java:534)


root cause
java.lang.ClassCastException: cannot assign instance of net.sf.jasperreports.engine.base.JRBaseStaticText to field net.sf.jasperreports.engine.base.JRBaseLineBox.boxContainer of type net.sf.jasperreports.engine.JRBoxContainer in instance of net.sf.jasperreports.engine.base.JRBaseLineBox
at java.io.ObjectStreamClass$FieldReflector.setObjFieldValues(ObjectStreamClass.java:1885)
at java.io.ObjectStreamClass.setObjFieldValues(ObjectStreamClass.java:1076)
at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1851)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1769)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1646)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1274)
at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1845)