Interfaces - The Java Language Specification - page 276

}
interface InfiniteBuffer extends Buffer {
char get() throws BufferException; // override
}
9.4.1.2. Requirements in Overriding
The relationship between the return type of an interface method and the return types of any
overridden interface methods is specified in § 8.4.8.3 .
The relationship between the throws clause of an interface method and the throws clauses of
any overridden interface methods are specified in § 8.4.8.3 .
The relationship between the signature of an interface method and the signatures of over-
ridden interface methods are specified in § 8.4.8.3 .
9.4.1.3. Inheriting Methods with Override-Equivalent Signatures
It is possible for an interface to inherit several methods with override-equivalent signatures
(§ 8.4.2 ) . Such a situation does not in itself cause a compile-time error. The interface is con-
sidered to inherit all the methods.
However, one of the inherited methods must be return-type-substitutable for every other
inherited method; otherwise, a compile-time error occurs. (The throws clauses do not cause
errors in this case.)
There might be several paths by which the same method declaration is inherited from an
interface. This fact causes no difficulty and never, of itself, results in a compile-time error.
9.4.2. Overloading
If two methods of an interface (whether both declared in the same interface, or both in-
herited by an interface, or one declared and one inherited) have the same name but differ-
ent signatures that are not override-equivalent (§ 8.4.2 ) , then the method name is said to be
overloaded .
This fact causes no difficulty and never of itself results in a compile-time error. There is no
required relationship between the return types or between the throws clauses of two methods
with the same name but different signatures that are not override-equivalent.
Example 9.4.2-1. Overloading an abstract Method Declaration
Click here to view code image
interface PointInterface {