The Java Language Specification, Third Edition

8.4.8 Inheritance, Overriding, and Hiding CLASSES
228
String id(String x) {...}
Integer id(Integer x) {...}
}
This is also illegal, since D.id(String) is a member of D, D.id(Integer) is
declared in D and:
• the two methods have the same name, id
• the two methods have different signatures.
• D.id(Integer) is accessible to D
• D.id(String) overrides C.id(String) and D.id(Integer) overrides
I.id(Integer) yet the two overridden methods have the same erasure
The access modifier (§6.6) of an overriding or hiding method must provide at
least as much access as the overridden or hidden method, or a compile-time error
occurs. In more detail:
• If the overridden or hidden method is public, then the overriding or hiding
method must be public; otherwise, a compile-time error occurs.
• If the overridden or hidden method is protected, then the overriding or hiding
method must be protected or public; otherwise, a compile-time error
occurs.
• If the overridden or hidden method has default (package) access, then the
overriding or hiding method must not be private; otherwise, a compile-time
error occurs.
Note that a private method cannot be hidden or overridden in the technical
sense of those terms. This means that a subclass can declare a method with the
same signature as a private method in one of its superclasses, and there is no
requirement that the return type or throws clause of such a method bear any relationship
to those of the private method in the superclass.
DRAFT
8.4.8.4 Inheriting Methods with Override-Equivalent Signatures
It is possible for a class to inherit multiple methods with override-equivalent
(§8.4.2) signatures.
It is a compile time error if a class C inherits a concrete method whose signatures
is a subsignature of another concrete method inherited by C.