@Override
  public void removeCredential(String alias) throws AmbariException {
    if (alias != null) {
      Lock lock = getLock();
      lock.lock();
      try {
        cache.invalidate(alias);
      } finally {
        lock.unlock();
      }
    }
  }
Removes the specified credential from this CredentialStore
<p/>
This implementation is thread-safe, allowing one thread at a time to access the credential store.

@param alias a string declaring the alias (or name) of the credential
@throws AmbariException if an error occurs while removing the new credential
ambari-server/src/main/java/org/apache/ambari/server/security/encryption/InMemoryCredentialStore.java