Static initializer deadlock proof of concept

AbstractChildHolder.java

package com.fsecure.pavlukhin.concurrentclinit;

abstract public class AbstractChildHolder {
    public static class Child1 extends AbstractChildHolder {
        static {
            try {
                Thread.sleep(10);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        public void foo() {
            System.out.println(Thread.currentThread() + ": foo!");
        }
    }

    public static class Child2 extends AbstractChildHolder {
        static {
            try {
                Thread.sleep(10);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        public void foo() {
            System.out.println(Thread.currentThread() + ": foo?");
        }
    }

    public static final AbstractChildHolder C1 = new Child1();
    public static final AbstractChildHolder C2 = new Child2();

    abstract public void foo();
}

AbstractChildHolderTest.java

package com.fsecure.pavlukhin.concurrentclinit;

import org.junit.Test;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;

/*
 * Deadlock while static initialization proof of concept
 */
public class AbstractChildHolderTest {
    @Test(timeout = 5000L)
    public void concurrentInitialization() throws Exception {
        ExecutorService executor = Executors.newFixedThreadPool(2);
        Future<?> f1 = executor.submit(() -> new AbstractChildHolder.Child1().foo());
        Future<?> f2 = executor.submit(() -> new AbstractChildHolder.Child2().foo());
        f1.get();
        f2.get();
    }
}