We can purge below log files after stopping all the Oracle Application server services,
%ORACLE_HOME%\Apache\Apache\logs
%ORACLE_HOME%\opmn\logs
%ORACLE_HOME%\dcm\logs
%ORACLE_HOME%\sysman\logs
%ORACLE_HOME%\j2ee\ [ OC4J instance name ]\log
%ORACLE_HOME%\j2ee\ [ oc4j instance name ]\application-deployments\ [ application name ] \[ oc4j instance name ]_default_island_1\*
