A little gem I found in the Oracle Metalink Notes: Steps to enable OC4J logging: a- Each OC4J instance has a separate logging configuration file: $ORACLE_HOME/10.1.3/j2ee/ /config/j2ee-logging.xml b- By default the log level is set to something like: c- You can set level to the desired value as using following syntax: : Message type: INTERNAL_ERROR, ERROR, WARNING, NOTIFICATION & TRACE Message level: 1-32 (1 most severe, 32 least) d- Each OC4J instance has file: $ORACLE_HOME/10.1.3/j2ee/ /application-deployments/ /orion-application.xml Which contains tag like: to specify the log file name. e- Each OC4J has its own log file in the following path: - Plain Text Log: $LOG_HOME/ora/10.1.3/j2ee/ / _ /application.log - ODL Log: $LOG_HOME/ora/10.1.3/j2ee/ / _ /log.xml