ThrowingConsumer.java

@FunctionalInterface
interface ThrowingConsumer<T, E extends Exception> {
    void accept(T t) throws E;

    static <T> Consumer<T> unchecked(ThrowingConsumer<T, Exception> t) {

        return arg -> {
            try {
                t.accept(arg);
            } catch (Exception ex) {
                throw new RuntimeException(ex);
            }
        };
    }
}

// threads.forEach(ThrowingConsumer.unchecked(Thread::join));