Description Derek Inksetter 2005-06-14 11:39:17 EDT

If I have two interfaces with the same method, but with mismatching exception
signatures, it's legal for me to have an implementation of those two interfaces
that has a method with no exception thrown in its signature.  It's also legal
for me to have an intermediate interface that inherits from the two other
interfaces.

class AException extends Exception { }
class BException extends Exception { }

interface A {
    public void xyz() throws AException;
}
 
interface B {
    public void xyz() throws BException;
}
 
interface C extends A, B { }
 
class D implements C {
    public void xyz() {
        System.out.println("In XYZ");
    }
}

If I have a caller that uses the implementation type, it's clear that the caller
shouldn't expect an exception to be thrown.  If, however the caller uses the
intervening interface type, Eclipse and javac seem to differ on the interpretation.

public class InheritenceTest {

    public static void main(String[] args) {
        C c = new D();
        c.xyz();
    }
}

In that bit of sample code, javac (Sun 1.5.0_03) compiles it and runs with no
trouble.  Eclipse gives an error saying "Unhandled exception type AException"
and refuses to build.