Multiple Inheritance?
Multiple Inheritance is where one class has more than one superclass and inherits features from all parent classes.
Some programming languages, like C++ and Ruby, support Multiple Inheritance. Java, however, does not support multiple inheritance. Java does not permit you to extend more than one class (although that class itself may be a subclass, hence allowing multi-level inheritance).
The reasons for not permitting Multiple Inheritance is mostly technical (compiler design) and, at this point, historical artifacts. You can refer to Oracle's Java Tutorial: Inheritance for their explanation of why Multiple Inheritance is not permitted.
Note that it is perfectly okay for a class to have multiple subclasses.
Resources
- TutorialsPoint has a well written entry on Inheritance, with a nice diagram for Types if Inheritance.