Bug 1842701 concerns integrating FMJ in Sun JMF.
I use FMJ to send/receive Video RTP stream from a WebCam.
I placed FMJ in my classpath, and Sun JMF is installed on my system.
I don't know if FMJ without JMF works on RTP streaming, but it doesn't when I use FMJ's RTPSessionMgr inside Sun's JMF framework.
This patch (that I also attached in Bug 1842701) solved the problem for me.