How to trace JGROUPS McastReceiverTest/McastSenderTest calls?

Question

Attempting to capture logging information when using the JGROUPS Test classes

McastReceiverTest

McastSenderTest

Receivers

java -Dlog4j.configurationFile=/home/user1/log.txt -cp jgroups-4.1.2.Final.jar org.jgroups.tests.McastReceiverTest -bind_addr myServer1 -mcast_addr 228.8.8.8 -port 45588

java -Dlog4j.configurationFile=/home/user1/log.txt -cp jgroups-4.1.2.Final.jar org.jgroups.tests.McastReceiverTest -bind_addr myServer2 -mcast_addr 228.8.8.8 -port 45588

Sender

java -Dlog4j.configurationFile=/home/user1/log.txt -cp jgroups-4.1.2.Final.jar org.jgroups.tests.McastSenderTest -bind_addr myServer2 -mcast_addr 228.8.8.8 -port 45588

log.txt file

appender.rolling1.fileName=/home/user1/jgroups.log
appender.rolling1.filePattern=/home/user1/jgroups.log.%i
appender.rolling1.layout.pattern=%m%n
appender.rolling1.layout.type=PatternLayout
appender.rolling1.name=jgroups
appender.rolling1.policies.size.size=1024KB
appender.rolling1.policies.size.type=SizeBasedTriggeringPolicy
appender.rolling1.policies.type=Policies
appender.rolling1.strategy.max=5
appender.rolling1.strategy.type=DefaultRolloverStrategy
appender.rolling1.type=RollingFile
    
logger.rolling.name=jgroups
logger.rolling.level=DEBUG
logger.rolling.appenderRef.rolling.ref=jgroups

The test works great, but no log files generated. Is the wrong property being used for the Logger or is the Logger config file incorrect?