As in Java, you can extends a class and implements several interfaces.
That means there is no multiple inheritance as in C++ for example. We believe multi inheritance is bad. It often denotes a bad inheritance tree (meaning it is possible to add intermediate inheritance nodes to solve the multi inheritance problem). Furthermore it brings a whole class of problem (multiply defined symbols) that are hard to solve and are bad for efficiency.
We really think one should limit as much as possible to extend classes and rather choose to implement.
See class definition for the classes/interfaces syntax. Please note that classes can be abstract. That means that an abstract classes can never be instantiated, and can provide a partial implementation of an interface.
One should use Automatic delegations to bypass some limitations of single inheritance.