reference to method is ambiguous, why?

Greenhorn

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posted 1 month ago

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Hi,

I remembered an old OCA question today about ambiguous types in function arguments, chained together with passing null as argument, kinda like here.

I tried the same but with a tree like structure:

class test {

class Base extends Object {
    }

class TL1 extends Base {

}
    class TR1 extends Base {
    }

class TL2 extends TL1 {
    }

class TR2 extends TL1 {
    }

class TL3 extends TL2 {}

class TL4 extends TL3 {}

public void method(Object e) {
        System.out.println("Base");
    }

public void method(TL1 e) {
        System.out.println("TL1");
    }

public void method(TR1 e) {
        System.out.println("TR1");
    }

public void method(TL2 e) {
        System.out.println("TL2");
    }

public void method(TR2 e) {
        System.out.println("TR2");
    }

public void method(TL3 e) {
        System.out.println("TL3");

}

public void method(TL4 e) {
        System.out.println("TL3");
    }

public void lol2() {
        try {
            method(null);
        } catch (Exception e) {
            System.out.println(e.getMessage());
        }

}

public static void main(String[] args) {
        new test().lol2();
    }

}

The compiler is not happy about the leafs, even though they are not on the same level, it either complains about that it cannot decide to chose between TL4 and TR2, or if i remove TR2 between TL4 and TR1.
Why is that, isnt TL4 always the "most specific" class because its 4 levels deep into the inheritance chain?

Carey Brown

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posted 1 month ago

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You have a typo on line 49. "TL3" should be "TL4".

Other than that if you only have the left hierarchy or the right it will work but not both.

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Carey Brown

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posted 1 month ago

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This works. Outputs "TL4".

JavaRanch-FAQ HowToAskQuestionsOnJavaRanch UseCodeTags DontWriteLongLines ItDoesntWorkIsUseLess FormatCode JavaIndenter SSCCE API-17 JLS JavaLanguageSpecification MainIsAPain KeyboardUtility