I upgraded recently to the new Eclipse version (Oxygen). I downloaded the lombok.jar from the website and installed it. This is how the eclipse.ini looks like a
eclipse.ini
If restarting Eclipse doesn't help. You have to quit the application and make sure to kill all running java processes. That worked for me.
(Eclipse Oxygen 4.7.1a, OpenJDK 1.8.0_151-b12)