Java There is so much about Java in the Net. Eiffel supports renaming a method in derived class. Unlike Eiffel, Sather does not allow covariant argument data types in the overriding method. Java's inner classes, anonymous classes are from this language. In addition to virtual methods, Beta also has virtual classes.
Derived class can override inner class defined in base class.
Derived class method never overrides base class method completely. Incremental implementation, preserving base class semantics is possible because of this. BETA Home Page CLOS Object oriented extension of Common Lisp.