Where can I get proven libraries for Java? Are there out-of-the-box encryption solutions?

Question

Java

Question for those who are familiar with the java language and have development experience.
I'm just starting to learn java and wondered if there are ready-made libraries, for example, for encryption. Let's say I want to create a stegocontainer and pass text in it. Or transfer the file encrypted using RSA. Of course, you can try to implement it yourself, but it is difficult to make a really worthwhile system. So the question is, are there any good libraries that allow you to do this? And in general, where can you get proven libraries written correctly for java?
Thanks

Answer 1

Are there any good libraries that allow you to do this?

in the JDK.

Answer 2

www.mkyong.com
you will find a lot of useful things in this stroke, maybe the answer to your question