The default implementation of Map.replaceAll:

    default void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) {
        Objects.requireNonNull(function);
        for (Map.Entry<K, V> entry : entrySet()) {
            K k;
            V v;
            try {
                k = entry.getKey();
                v = entry.getValue();
            } catch(IllegalStateException ise) {
                throw new ConcurrentModificationException(ise);
            }
            entry.setValue(function.apply(k, v));
        }
    }

fails with UOE on ConcurrentSkipListMap because its entrySet returns immutable map entries. The default should instead do:

    map.put(k, apply(k, v))

As part of a separate issue, HashMap, TreeMap, LinkedHashMap, ConcurrentHashMap, and ConcurrentSkipListMap should consider overridding Map.replaceAll, because the default is likely to be not as performant.