When i used code as the follow,i got
WARN [org.jboss.cache.CacheImpl.JBossCache-Cluster] - node /__JBossInternal__/__RefMap__/___JBossInternal___User_151__ID__5c4o34-7432bj-fkailpco-1-fkait9qo-1ow not found
User uInCache = cacheManager.getUser(uid); uInCache.getDepartment().getUsers().remove(uInCache)