Source.java

package com.bloidonia.meddling;

@FunctionalInterface
public interface Source<T> {
    default void yield(T value) {
        System.out.println(value);
    }

    default void run() {
        apply(this);
    }

    void apply(Source<T> s);

    static void main(String[] args) {
        Source<Integer> intSource = (self) -> {
            self.yield(1);
            self.yield(2);
            self.yield(3);
        };
        intSource.run();
    }
}