Java Language Specification, Version Java SE 21 Edition

8.4.8. Inheritance, Overriding, and Hiding

4 Documented Misconceptions

AbstractClassMustImplementAbstractMethod

An abstract class must implement all abstract methods defined in its superclass

ConcreteClassOnlyImplementDirectAbstract

A concrete class only needs to implement abstract methods declared in its direct supertypes

ImplicitInterfaceImplementation

Java implicitly produces implementations of any methods a class inherits from the interfaces it implements

NoMethodInheritance

Subclasses inherit fields but not methods