I want to learn Java.
Will my question be deleted if I ask for recommendations on StackOverflow?
If so, is there another StackExchange site I can ask on?
If you want to learn Java, then start with a nice tutorial on Java. Don't ask for recommendations. That's not what we're here for.
Instead, dig into that tutorial, get your hands dirty, and get stuck in the mud. Once you're stuck, you'll actually be able to relate to a specific problem you're facing, and you'll be able to ask a well researched question, despite it being a beginner question.
When you ask questions that you've put effort into, you'll find that the answers you get are much more meaningful. You'll actually be able to understand what the answerers are saying to you, instead of then spamming each party with "What do you mean, can you tell me more about X?"
What's more, this is your way of giving back to the community. If you ask well-researched questions about a problem you're facing, there's a good chance someone else is facing that same problem! In short, by helping us help you, you also help others in the process, and that's awesome!
In short, recommendation questions would be quickly closed as having little value to future visitors. Hope this helps.
There really isn't a site that this would belong on, since it's too inspecific. Some open-ended questions that I can think of:
There's also the issue of requesting books, tutorials, and the like, all of which are too subjective to be pinned down to one thing.
Don't get me wrong, I totally admire that you want to learn Java, and I would strongly suggest that you read the Java tag wiki to get your feet wet. Asking that sort of question on SO would be a quick candidate for closure due to "Not a Real Question".