After a out of the box installation and configuration of the Oracle Application Server, most of the log files of the AS are configured to be rotated. This means that after a period or when they reach a particular size, the log file is copied and a new log files is created.
This gives the AS administrators flexibility to maintain these files; backup etc..
There is one log file, the so called standard output / standard err, also known as print output to console, that is not configured to be rotated. But this files is growing and growing, it could easily grow into hundreds of giga bytes.
The name of this files is:
$ORACLE_HOME/opmn/logs/default_group~OC4J_INSTANCE_NAME~default_group~1/log
It is possible to make this file rotatable.
Add the following parameters in the configuration of your OC4J instance,
In java-options:
-Dstdstream.filesize=8
Note: 8 means, rotate after 8 MB in size.
In oc4j-options:
-out $ORACLE_HOME/opmn/logs/oc4j_soa.out
-err $ORACLE_HOME/opmn/logs/oc4j_soa.err
Seperate standard outout and error messages.
See also the Oracle docs on this.