Java 9 modularity vs refactor existing apps

[Paulo Cesar Dias Lima]

Whats the best aproach to refactor existing apps to get advantage of Java 9 modularity?

[Campbell Ritchie]

Would you need to refactor apps? Can you get away with simply altering the imports to be modular? I don't know.

[Paulo Cesar Dias Lima]

Hi Ritchie. I mean Java EE Server side apps.

How to apply new features like common logging system, light-weight JSON API, HTTP 2 Client support  for Java EE apps. Will be available only to Java EE 9?

Thanks.

[Campbell Ritchie]

Don't know. Kishori is answering questions, so I expect he will know more.

[Tim Moores]

You can generally use newer SE features on older EE versions; I see no reason why that should be different with Java SE 9. There isn't much to "applying" new features - you would just use them where it makes sense. (That implies not rushing out to use any and all new features, but that has always been true.)

As to the new module stuff, it may well be that it doesn't make sense for your apps. Note that a criticism of the former proposed implementation was that it makes sense for the JRE itself, but not so much for application code. So proceed with caution. If so far you haven't seen a need to check out OSGi, maybe you don't need it (although, to be fair, both approaches do not cover exactly the same ground, but they do aim to solve similar problems).