The Java Version Almanac javaalmanac.io provides comparisons between different Java versions of the things that have been added or removed to the system library: see Java 17 vs. Java 11.
See also the release notes of removed features and options of Java 12 to 17:
- Java 12 – Removed Features and Options
- Java 13 – Removed Features and Options
- Java 14 – Removed Features and Options
- Java 15 – Removed Features and Options
- Java 16 – Removed Features and Options
- Java 17 – Removed Features and Options
Please also note the Strongly Encapsulate JDK Internals (JEP 396 and JEP 403): when using reflection, Java 17 is more restrictive than Java 11.