The sequence number of logging events remains at 0 (zero) even after configuring a SequenceNumberGenerator in the LoggerContext.

I tried to configure a sequence number generator in the logback.xml configuration file as follows:

<configuration>
   <sequenceNumberGenerator class="ch.qos.logback.core.spi.BasicSequenceNumberGenerator"/>
  ...
</configuration>

 
Although this configuration is accepted without error/warning, a call to LoggerContext#getSequenceGenerator() at runtime always returns null.

After some investigations it appears that LoggerContext#getSequenceNumber() is hardcoded to always return null (see here):

public SequenceNumberGenerator getSequenceNumberGenerator()
{
   return null;
}

Also LoggerContext extends ContextBase which also maintains a reference to a SequenceNumberGenerator together with the associated setter and getter methods.

Looks like there is some confusion about which class should own the generator...