public boolean contains(final String className) {
        final Shard shard = getShard(className);

        synchronized (shard) {
            return shard.containsKey(className);
        }
    }
@author Jongho Moon
@author jaehong.kim
agent-module/plugins/spring/src/main/java/com/navercorp/pinpoint/plugin/spring/beans/interceptor/Cache.java