ankur rathi wrote:. . . Oracle . . . are going to release . . . long term support version every 2 years. . . . .
I think that is every three years.
1: Follow the newer fora on this website. The newer features in Java8, for example, are usually discussed here.
2: Ask questions on those same fora.
3: Read books about the newer features. For Java8/9, for example, I have Java8 in Action (Urma Fusco and Mycroft), an “Impatient” book by Cay Horstmann and Maurice Naftalin's book about Lambdas. Publishers like Manning, Packt, O'Reilly and Apress will print book describing the newer versions' features soon after they are introduced.
4: Consider whether general books like those above give an easier introduction than a cert book. I would prefer general books and say that cert books are specifically there for sitting the exam.
5: Write lots of code using the newer features.
Urma Fusco and Mycroft's book now has a different title for its nwere editions.
That's the best advice I can give you. Writing software is not a static task. The languages/techniques you use 5, 10, or 20 years from now will be vastly different than they are today, and very different from where they were years ago. Functional programming, NoSQL databases, and microservices are just some of the topics that have drastically changed the landscape of software development. Writing software should excite you, and so should learning about new things to make your life easier.
If you want to stay current, you need to read new material. There's plenty of articles, publications, mailing lists, and blogs to subscribe to. I get a lot of notification about new features in Java from Twitter these days, as it helps to follow well known Java developers and enthusiasts. You also shouldn't be afraid to try out new things at work. Most managers tend to be resistant to change, but if everyone stood still, then there'd still be systems running FORTRAN! (yes FORTRAN is dead.. I don't care what anyone says )
For Oracle Java releases, the LTS releases are every 3 years. I download and use the non-LTS releases for fun, although for production systems I stick with LTS releases only. In other words, you don't need to change versions of Java every 6 months if you don't want to. But you should know what the key features of each is, even if you've never used it.