Who has example tasks for learning Java?

Question

Java

In general, I began to study Java. I want to rise to a good level in a fairly short time. Since the programming experience is pretty good - trivial tasks, like output HW! screen is not needed. I would like to get a feel for the aesthetics of the language, implicit behavior, etc. and related areas, offhand, multithreading, for example.
Feel free to invent - although the Internet is full of examples of all sorts of different tasks, it's interesting to hear suggestions.
Thank you.

Answer 1

Example tasks in Java, tests in Java:
java-quizapp.rhcloud.com

Answer 2

Might be interesting