public static <K, V> V computeIfAbsent(final Map<K, V> map, final K key, final Function<? super K, ? extends V> mappingFunction) {
        V v = map.get(key);
        if (Objects.nonNull(v)) {
            return v;
        }
        return map.computeIfAbsent(key, mappingFunction);
    }
This is jdk8 performance bug, see: https://bugs.openjdk.java.net/browse/JDK-8161372.

@param map source map
@param key key
@param mappingFunction mappingFunction
@param <K> k
@param <V> v
@return v
shenyu-common/src/main/java/org/apache/shenyu/common/utils/MapUtils.java