Interface default method not exist when extended by another interface

[Juntao Hu]

Suppose we have class C -|> interface IB -|> interface IA, while IA has a default method foo which is not overwriten by any of its children, then invocation on c.foo() would fail with Method foo([]) does not exist.

interface IA {
    default String foo() {
        return "foo " + bar();
    }
    String bar();
}

interface IB extends IA {}

public static class C implements IB {
    public String bar() {
        return "C#bar()";
    }
}

[Hyukjin Kwon]

Interesting. Does this work in the regular reflection but not work in Py4J?

[Juntao Hu]

Interesting. Does this work in the regular reflection but not work in Py4J?

C.class.getMethod("foo").invoke(new C()) works.

I guess it's here that super classes of interfaces are not scanned.

py4j/py4j-java/src/main/java/py4j/reflection/ReflectionEngine.java

Lines 350 to 352 in b4514ec

 for (Class<?> intf : clazz.getInterfaces()) { 
 	methodsToCheck.addAll(Arrays.asList(intf.getDeclaredMethods())); 
 }