SequencingManager is private to EclipseLink. It provides most of sequencing functionality. It's accessed by DatabaseSession through getSequencingHome() method. Here's the lifecycle of SequencingManager. InitialState: SequencingManager doesn't exist. Action: SequencingManager created -> Not connected State. State: Not connected. isConnected() returns false; getSequencingControl() could be used; getSequencing() == getSequencingServer() == getSequencingCallbackFactory() == null; Action: onConnect is called -> Connected State. State: Connected. isConnected() returns true; getSequencingControl() could be used; getSequencing() could be used; in case ownwerSession is a ServerSession getSequencingServer() could be used; Action: onDisconnect is called -> Not connected State. Here's a sketch of SequencingManager architecture. The main 4 objects comprising SessionManager are: valueGenarationPolicy; preallocationHandler; connectionHandler; state; That's how they evolve during lifetime of SequencingManager object: Not connected State: preallocationHandler doesn't have any preallocated sequencing values. connectionHandler == null; state == null; Connected State: preallocationHandler may contain preallocated sequencing values. valueGenarationPolicy != null; state != null; The most important method of the class is onConnect(): that's where, using values of the attributes'(accessible through SequencingControl): shouldUseSeparateConnection; login; minPoolSize; maxPoolSize; as well as boolean flags returned by valueGenerationPolicy methods: shouldAcquireValueAfterInsert(); shouldUsePreallocation(); shouldUseSeparateConnection(); shouldUseTransaction(); one of implementors of inner interface State is created. Once in Connected State, neither changes to attributes, nor to returns of valueGenerationPolicy's four should... methods can change the state object. To change the state object, onDisconnect(), than onConnect() should be called. There is no need to do it directly: each of the following methods available through SequencingControl does that: setValueGenerationPolicy; setShouldUseNativeSequencing; setShouldUseTableSequencing; resetSequencing;