java - How to avoid HeadlessException in thread? -

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i have tried open dialog box in servlet & opens fine. tried achieve same thing in thread's run method. gaved me following error:

java.awt.headlessexception @ java.awt.graphicsenvironment.checkheadless(graphicsenvironment.java:159) @ java.awt.window.<init>(window.java:431) @ java.awt.frame.<init>(frame.java:403)

below code : 

jframe frame = new jframe("success message"); frame.setsize(200, 50); frame.add(new jlabel("data uploaded "+inputfile.getfilename())); frame.setvisible(true); frame.setdefaultcloseoperation(jframe.exit_on_close);

i tried below code, failed

graphicsenvironment ge = graphicsenvironment.getlocalgraphicsenvironment(); system.out.println("headless mode: " + ge.isheadless()); if(!ge.isheadless()){      system.setproperty("java.awt.headless", "true"); }

exception described : thrown when code dependent on keyboard, display, or mouse called in environment not support keyboard, display, or mouse.

java servlet code runs @ webserver, not @ webclient (webbrowser). webserver listening on http requests, producing html/css/js responses , sending webclient. webclient sending http requests , processing retrieved html/css/js responses.

if execute swing gui in servlet, displayed in webserver, not in webclient.

there 3 solutions particular problem:

  1. run swing gui code @ webclient instead. can in flavor of applet or web start served jsp/html page.

  2. use client side programming/scripting language instead, e.g. javascript or actionscript (flash). in javascript there's alert() function displays dialog.

  3. use taglibs jstl <c:if> and/or el in jsp render html/css/js content conditionally. can combinied solution #2.


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