i've learned

Creating objects and classes,
creating methods,
Overloading constructors,

what next should i learn ??

What are your goals? Why are your learning Java? What do you want to know?

because i love programming...! :)
i want to learn everything about java

It would help if you had some kind of goal. Think of a project you would like to write in Java. That will guide you as to what to learn next when you run into something you don't know how to do. If you don't have any ideas, search for collaborative open source projects on the web. There are many projects out there where Java programmers are welcome to contribute.

Linked list
binary search tree
Overridden method
Thread and animation