Hi Rich, this was brought up to us by one of our CSEs, Chris Lui.
Issue: A Websphere environment was being set up and issues with Websphere compiling JSP's even after doing the steps documented here were still persisting. This should not have been affected by it since the environment was on Fix Pack 11 which should have resolved it (
LPS-70264 for reference).
Resolution: It was resolved by following these steps:
1. After you've deployed the Liferay .war, shutdown Websphere 8.5.5
2. Go to the directory as mentioned in Jeremy's comment. Your directory may slightly differ, but it should be close.
3. Edit the file and add in <jsp-attribute name="jdkSourceLevel" value="18" />
4. Start Websphere.
Found here for reference:
Please make the changes you deem fit. Thank you!