I am using the 4.9.0 Version of the Eclipse IDE with a JDK 11 and was trying to install the e(fx)clipse 3.4.1 Plugin. Somehow it could not find all resources, to install it properly and I got the following message:
Are the components with those versions not compatible?
Thanks in advance
Try installing version (3.4.1) release from this Update site.
Also check this issue on GitHub.