tuples in Java streams

Tuples.java

// as long answer to https://twitter.com/pivovarit/status/1067883547669815296

import java.lang.reflect.Field;
import java.util.Arrays;

class Tuples {

    public static void main(String... args) throws NoSuchFieldException, IllegalAccessException {
        new Tuples().exec();
    }

    // - if executed as instance method the instances of the anonymous class keep a reference to the enclosing Tuples
    //   instance, if the objects are exposed outside the stream there is a risk for a memory leak
    //
    // - if executed in a static context the instances of the anonymous class don't keep a reference to the enclosing
    //   Tuples instance
    void exec()   {
        Arrays.asList("1", "22").stream()
            .map(v -> new Object() {
                String name = v;
                int length = v.length();
            })
            .peek(Tuples::showRef)
            .filter(tuple -> tuple.length % 2 == 0)
            .forEach(tuple -> System.out.println(tuple.name));
    }

    static void showRef(Object o) {
        try {
            Field field = o.getClass().getDeclaredField("this$0");
            if (field.canAccess(o)) {
                field.setAccessible(true);
            }
            System.out.println("enclosing " + field.get(o).getClass());
        } catch (Exception e) {
            System.out.println("oops... " + e);
        }
    }

}