Eclipse - `open call hierarchy` stop searching in lambda chain

Question

Here is my sample java code:

public class Test {

    public static void main(String[] args) {
        methodDepth0(
            ()->
                methodDepth1(
                    ()->
                        methodDepth2()
                )
        );
    }

    static Object methodDepth2() {
        return null;
    }

    interface MyIF {
        void call();
    }

    static void methodDepth0(MyIF myIf){
        myIf.call();
    }

    interface MyIF2 {
        void call();
    }

    static void methodDepth1(MyIF2 myIf2){
        myIf2.call();
    }
}

When I open call hierarchy of method methodDepth2() from Eclipse(4.4), open call hierarchy stop searching next caller:

What I expect is like opening call hierarchy of method methodDepth1() which show until the main method.

Answer 1

From what I can tell the lack of call hierarchy depth is due to (re)evaluation of code at runtime. It is explained in 15.27.4 Run-Time Evaluation of Lambda Expressions in the Java Language Specification.

At run time, evaluation of a lambda expression is similar to evaluation of a class instance creation expression, insofar as normal completion produces a reference to an object. Evaluation of a lambda expression is distinct from execution of the lambda body.

Answer 2

As the second picture clearly shows, Eclipse is able to trace the call hierarchy through the method call myIf.call() inside methodDepth0 . This is correct, because the (outer) lambda implements method MyIF.call() .

The fact that the same pattern does not work in the next nesting level looks like a bug. Please consider filing a bug for JDT/UI. TIA.

Just note, that for lambdas implementing library types like Consumer<T> , the number of callers into accept(T) in a workspace may easily become unmanageable, similar to any call hierarchy through, eg, Runnable.run() - but that doesn't question the general usefulness of call hierarchies through lambdas.