javafx.osgi and joverflow.ui plugins need some access rules for javafx to avoid Access Restriction errors at least in my Eclipse set up (Mac + Eclipse 4.8 M6 + running Eclipse w/ JDK 11)

 

Should change in .classpath for the two plugins, from 

<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.8"/>

to

<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.8">
    <accessrules>
        <accessrule kind="accessible" pattern="javafx/**"/>
    </accessrules>
</classpathentry>