I just installed the OpenJDK version of the JDK 11 General-Availability Release on Windows 10. I tried to install it as a JRE in the just-released Eclipse 2018-09 (4.9.0), and a
Eclipse 2018-09 doesn't support JDK 11 out of the box, but the official plugin for JDK 11 has now been released on the market place:
https://marketplace.eclipse.org/content/java-11-support-eclipse-2018-09-49
Here is the release announcement: https://www.eclipse.org/lists/jdt-dev/msg01049.html
OracleJDK and OpenJDK are supported in the same way (Other JDKs like OpenJ9 should work, too)
If a new JDK release is not supported, you cannot use its new language features and you may not be able to use it all for development because of class format changes. Launching is likely to work.
The update site for the plugin for 2018-09 is here: http://download.eclipse.org/eclipse/updates/4.9-P-builds/P20180926-0920/