请你帮我解决这个问题。为什么会导致问题？
io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:759)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [rt.jar:1.8.0_45]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [rt.jar:1.8.0_45]
at java.lang.Thread.run(Thread.java:745) [rt.jar:1.8.0_45]
Caused by: java.lang.IllegalStateException: UT010006: Cannot call getWriter(), getOutputStream() already called
at io.undertow.servlet.spec.HttpServletResponseImpl.getWriter(HttpServletResponseImpl.java:344)
at org.apache.jasper.runtime.JspWriterImpl.initOut(JspWriterImpl.java:126)
at org.apache.jasper.runtime.JspWriterImpl.flushBuffer(JspWriterImpl.java:119)
at org.apache.jasper.runtime.JspWriterImpl.flush(JspWriterImpl.java:159)
at org.apache.jsp.sfmain.jsp.integrated_005fapp_005fadmin_005flist_jsp._jspService(integrated_005fapp_005fadmin_005flist_jsp.java:185)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:69)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:366)