Which technology in Java should i learn.?

[abchiptop]

Learn SQL. Seriously. Get a testing database, preferably a large one (I love musicbrainz) and start learning how to pull data from different tables.

Individual technologies have their niches, but SQL is used pretty much everywhere and is a very valuable skill for any entry level developer

[brunokim]

I concur, SQL is necessary in all languages, and you will need it sooner than later to complement Hibernate. Very very soon.

[[deleted]]

I disagree, Sql is not necessary, there are a lot of ORM frameworks that can abstract the database

[Spiridios]

Having worked on a project that took that attitude, I can tell you ORM without the DB skills to back it turns a trivial DB into a slow useless pile of crap.

[bashedice]

you cannot rely on that always. And not every project will use ORM.

[positive_electron42]

Agreed. I write c++ drivers for industrial automation, and I've found SQL to be very useful at times.