In OSGi environment logback-core will correctly try to use the class-loader of logback-classic bundle to load classes of the selected Appenders. This however means that logback-classic needs to have visibility to the requested Appender classes. Since RollingFileAppender is located in a separate package "ch.qos.logback.core.rolling" and not explicitly referenced from logback-classic code, the respective Import-Package declaration will not be generated automatically by the BND tool (embedded in maven-bundle-plugin).

In order to avoid ClassNotFound exceptions when trying to use RollingFileAppender the appropriate Import-Package declarations have to be added explicitly to the configuration of maven-bundle-plugin in logback-classic POM.

The current <Import-Package> settings in maven-bundle-plugin configuration:

<Import-Package>sun.reflect;resolution:=optional,
javax.jms;resolution:=optional,
*
</Import-Package>

Suggested update:

<Import-Package>sun.reflect;resolution:=optional,
javax.jms;resolution:=optional,
ch.qos.logback.core.rolling,
ch.qos.logback.core.rolling.helper,
*
</Import-Package>

Please consider also to implement the related issue LBCLASSIC-121 when fixing this defect.