Check the javadocs of the default (no-argument) constructors; that's frequently where that's mentioned. If it isn't, check the source code (which comes in a file called src.zip as part of the JDK).
Again with the line breaks? Why do you keep adding all the extra line breaks at the end of your posts? It is really annoying. If you are doing it on purpose, please stop.
The default size is 0. After all, the size represents the number of elements actually stored. You mean the capacity, and Lester has told you how to get that information.
Size: actual number of elements
Capacity: number of elements that can be stored without needing to restructure the internals