内側の無名クラスから外側の無名クラスを見る

A.java

import java.util.Comparator;

public class A {
    public static void main(String[] args) throws Exception {
        new Comparator<String>() {
            public int compare(String a, String b) {
                new Runnable() {
                    public void run() {
                        try {
                            Comparator cmp = (Comparator)this.getClass().getDeclaredField("this$0").get(this);
                            System.out.println(cmp.toString());
                        } catch (Exception e) {}
                    }
                }.run();
                return a.compareTo(b);
            }
        }.compare("a", "b");
    }
}