Have you read the documentation that people keep referring you to? Look here:
java.util.ArrayList#ArrayList(), and you'll see it tells you what the default initial capacity is. If you search for the other references to "capacity" on that page you'll find out a bit more. Notice that some things are implementation details that are not specified.
For an ArrayList or Vector, the capacity is the size of the underlying array. LinkedLists are implemented differently. If you read the documentation for that class you won't see any references to capacity. That's because the concept of capacity doesn't make sense in that case.