I have a black box application that runs on old obsolete Jetty 7. 
However, it has been working well since we installed it in 2014, and I 
need it to continue running. I have been asked to add an X-Frame-Options
 header to the interface, and every time I try to do this by changing 
Java I get class incompatibility errors. I can, however, make any 
changes I like to the JSP files, to web.xml, or to the Jetty 
configuration files in jetty/etc, but so far I have not found a change 
that works. I tried adding 
<* response.addHeader(“X-FRAME-OPTIONS”, “DENY”); *>
to various JSP files but it doesn't seem to help. Does anyone have any ideas? Eternal gratitude and many thanks if so.
-richard hoffman