Good article about how to create and process Java annotations from scratch
https://dzone.com/articles/creating-custom-annotations-in-java

To be honest knowledge about Java bytecode is not a necessity for the most Java developers. But if you want to know something about Java bytecode - here you can read about very basics.
https://dzone.com/articles/introduction-to-java-bytecode

Java 11 will be the next LTS release after Java 8 which is to be released on September 2018. Here you can read a short article about few new features from Java 11 such as new GC and removing the Java EE and CORBA modules, this article also explains what new release policy from Oracle means.
https://blog.takipi.com/java-11-will-include-more-than-just-features/

Have you ever heard about Project Amber in Java? Take a look at a few important features which can influence Java's future.
https://dzone.com/articles/what-is-project-amber-in-java

Gradle 4.7 Release Notes.
This release also supports running Gradle builds with JDK 10
https://docs.gradle.org/current/release-notes.html