I'm new to java. I have been reading some Java topics and doing some basic excercises, I think I have solid concepts in Java Standard Edition (exceptions, OOP, variables, methods, others). I want to learn java to create Android applications. What are your recommendations for some exercises before I begin with Android? or Can I begin with Android with that basic knowledge?
There is no set list of things to know - if you are comfortable with Java and think you can make an application then I think you can move on to Android. You should treat learning Android a lot like learning a few new libraries in the process of learning Java (such as a new UI library, some new threading libraries, etc...) So it is okay to be learning the ins and outs of Java as you learn Android: the prerequisite should just be being comfortable reading and writing code and thinking in Objects and abstractions.
That said, once you do decide to go into Android you should:
1) Pick up a good book. The FAQ page listed on our Android forum lists a few. Read through and skip till you get to some code. If you can read and understand the code (even if you don't know the classes) then you are probably okay.
2) Stop using the Oracle JavaDocs, and start using the JavaDocs on the Android developer's network: http://developer.android.com/reference/packages.html. It contains the Android API, the parts of the main Java API that are included in Android (not all classes in the Java API are found on Android), as well as the 3rd party libraries available.
3) Read the Training and API Guide sections of the Android developer's network. Start with the training then pick out the API Guides that are relevant to what you want to do. There are links to them from the API page I gave earlier
4) Read up on the Android Developer's Blog: http://android-developers.blogspot.com/. The current and the old stuff so you are familiar with the state of Android.