I just updated my JDK to the JDK 1.8 because i couldnt find the jfxrt.jar needed by java FX in the 1.7 version.
I downloaded the JDK from here: http://www.oracle.com/tec
You have to add requires jfxrt;
to your module-info if you have trouble after adding jfxrt.jar
For me on OSX it's under jdk1.8.0_05.jdk/Contents/Home/jre/lib/ext/jfxrt.jar
. I'd guess it's in an analogous place on your machine. Try /usr/java/jdk1.8.0_05/jre/lib/ext/jfxrt.jar
From the above comments, i tried this.
I added jfxrt.jar(Downloaded JDK) to PC. In eclipse, right click project --> properties --> Libraries --> Add external jar and choose the jar file.
The error went away.
Am using linuxmint 18.1 and i had the same issue. i realized that the open jdk i had didn't have the jfxrt.jar library. Download another jdk from oracle and then install it. Remember to change the path in the netbeans.conf file in the netbeans installation folder.