@Override
  public boolean removeToken(DelegationTokenIdentifier tokenIdentifier) {
    DelegationTokenInformation tokenInfo = tokens.remove(tokenIdentifier);
    LOG.trace("removeToken: tokenIdentifier = {}, removed = ", tokenIdentifier, (tokenInfo != null));
    return tokenInfo != null;
  }
Default in-memory token store implementation.
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/security/MemoryTokenStore.java