| Name | Description | Type | Package | Framework | 
| CachedMessageGroupMap | Class | org.apache.activemq.broker.region.group | Apache ActiveMQ | |
| CachedMessageGroupMapFactory | A factory to create instances of CachedMessageGroupMap when implementing the Message Groups functionality. | Class | org.apache.activemq.broker.region.group | Apache ActiveMQ | 
| EmptyMessageGroupSet | Class | org.apache.activemq.broker.region.group | Apache ActiveMQ | |
| GroupFactoryFinder | Class | org.apache.activemq.broker.region.group | Apache ActiveMQ | |
| MessageGroupHashBucket | Uses hash-code buckets to associate consumers with sets of message group IDs. | Class | org.apache.activemq.broker.region.group | Apache ActiveMQ | 
| MessageGroupHashBucketFactory | A factory to create instances of SimpleMessageGroupMap when implementing the Message | Class | org.apache.activemq.broker.region.group | Apache ActiveMQ | 
| MessageGroupMap | Interface | org.apache.activemq.broker.region.group | Apache ActiveMQ | |
| MessageGroupMapFactory | Interface | org.apache.activemq.broker.region.group | Apache ActiveMQ | |
| MessageGroupSet | Interface | org.apache.activemq.broker.region.group | Apache ActiveMQ | |
| SimpleMessageGroupMap | A simple implementation which tracks every individual GroupID value but which can become a memory leak if clients die before they complete a message | Class | org.apache.activemq.broker.region.group | Apache ActiveMQ | 
| SimpleMessageGroupMapFactory | A factory to create instances of SimpleMessageGroupMap when implementing the Message Groups functionality. | Class | org.apache.activemq.broker.region.group | Apache ActiveMQ | 
| SimpleMessageGroupSet | Class | org.apache.activemq.broker.region.group | Apache ActiveMQ | |