Hello, I read that there is a way to embed SWING components into scene using com.jmex.awt.swingui.JMEDesktop class, but I can’t find package com.jmex in jME3. Tell me please, where can I find it?
Its deprecated in jME3 and never worked well across platforms.
And there is no way to embed Swing components into jME3 application? 
Somebody did some rendering of the swing output to a texture, yadda yadda… but let me tell you its not what you want ^^
I want to make it possible to display pdf viewer on the Quad, for example. I found it for Java, but now I don’t know what to do.
This is what @normen mentioned above. Getting the contents to render onto a jME quad aren’t too big a deal… getting them to render efficiently is another story 
http://hub.jmonkeyengine.org/groups/user-code-projects/forum/topic/jme3-swing3d-gui/
and the swingGui thread is here: http://hub.jmonkeyengine.org/groups/development-discussion-jme3/forum/topic/another-gui-lib/