exception llegalStateException , any body know the reason

[RavindraJpatil patil]

I am getting this Exception i dont know exact cause of this , my functionality is working properly but console is showing this...
any idea about this ,

java.lang.IllegalStateException: getOutputStream() has already been called for this response
at org.apache.catalina.connector.Response.getWriter(Response.java:606)
at org.apache.catalina.connector.ResponseFacade.getWriter(ResponseFacade.java:195)
at org.apache.jasper.runtime.JspWriterImpl.initOut(JspWriterImpl.java:124)

[Ben Souther]

See:
http://faq.javaranch.com/java/IllegalStateException