A question about persistence use

[glmapper]

The code below is my state machine configuration class

@Autowired
private StateMachineRuntimePersister<States, Events, String> stateMachineRuntimePersister;

@Override
public void configure(StateMachineConfigurationConfigurer<States, Events> config) throws Exception {
    config.withPersistence().runtimePersister(stateMachineRuntimePersister);
    // set machineId or not?
    config.withConfiguration().machineId("orderStateMachine").autoStartup(true);
}

stateMachineRuntimePersister instance type is MongoDbPersistingStateMachineInterceptor。

The questions and doubts I have are：

• If 'machineId' is specified, then the persistence will be based on 'machineId' as the query key, resulting in multiple order state machines sharing a persistent state machine, thus influencing each other.
• If 'machineId' is not specified, a null pointer exception is thrown.