# Package org.apache.activemq.artemis.api.core

- Interface Summary
  Interface | Description
  --- | ---
  BaseInterceptor<P> |
  BroadcastEndpoint | BroadcastEndpint is used in BroadcastGroups and DiscoveryGroups for topology updates.
  BroadcastEndpointFactory |
  ICoreMessage | This interface is only to determine the API of methods required for Core Messages
  Interceptor | This is class is a simple way to intercepting calls on ActiveMQ Artemis client and servers.
  Message | A Message is a routable instance that has a payload.
  RefCountMessageListener | These methods will be called during refCount operations
  TransportConfigurationHelper | Helper interface for specifying default parameters on Transport Configurations.
  TrustManagerFactoryPlugin |

- Class Summary
  Class | Description
  --- | ---
  BroadcastGroupConfiguration | The basic configuration used to determine how the server will broadcast members This is analogous to `DiscoveryGroupConfiguration`
  ChannelBroadcastEndpointFactory | An implementation of BroadcastEndpointFactory that uses an externally managed JChannel for JGroups clustering.
  DiscoveryGroupConfiguration | This file represents how we are using Discovery.
  FilterConstants | Constants representing pre-defined message attributes that can be referenced in ActiveMQ Artemis core filter expressions.
  JGroupsBroadcastEndpoint | This class is the implementation of ActiveMQ Artemis members discovery that will use JGroups.
  JGroupsChannelBroadcastEndpoint | An implementation of JGroupsBroadcastEndpoint that uses an externally managed JChannel for its operations.
  JGroupsFileBroadcastEndpoint | This class is the implementation of ActiveMQ Artemis members discovery that will use JGroups.
  JGroupsFileBroadcastEndpointFactory |
  JsonUtil |
  RefCountMessage |
  TransportConfiguration | A TransportConfiguration is used by a client to specify connections to a server and its backup if one exists.
  UDPBroadcastEndpointFactory | The configuration used to determine how the server will broadcast members.