When reinitiating/reinitializing logback, one is supposted to call detachAndStopAllAppenders, that method in turn will end up calling close on all SyslogAppender's , but the implementation in SyslogAppender does not actually close the DatagramSocket by calling the close method, but leave it to GC to collect by killing references.

We refresh application configuration each 10 seconds ( reinitating the logging as well ) that makes all applications leak UDP sockets (filedsc).

Log4j fixed this in 1.2.17.