This is not an exam topic, but is needed to set up Unified Auditing as this is not done by default.
This procedure requires the Oracle kernel to be rebuilt.
Followed the procedure in 4.6.13.2 Migrating to Unified Auditing for Oracle Database:
[oracle@personal ~]$ lsnrctl stop
LSNRCTL for Linux: Version 12.1.0.2.0 - Production on 15-APR-2018 21:30:19
Copyright (c) 1991, 2014, Oracle. All rights reserved.
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=LISTENER)))
The command completed successfully
[oracle@personal ~]$ . oraenv
ORACLE_SID = [personal] ? jar
The Oracle base remains unchanged with value /opt/app/oracle
[oracle@personal ~]$ sqlplus / as sysdba
SQL*Plus: Release 12.1.0.2.0 Production on Sun Apr 15 21:31:07 2018
Copyright (c) 1982, 2014, Oracle. All rights reserved.
Connected to an idle instance.
SQL> startup
ORACLE instance started.
Total System Global Area 1543503872 bytes
Fixed Size 2924736 bytes
Variable Size 939528000 bytes
Database Buffers 587202560 bytes
Redo Buffers 13848576 bytes
Database mounted.
Database opened.
SQL> SELECT VALUE FROM V$OPTION WHERE PARAMETER = 'Unified Auditing';
VALUE
----------------------------------------------------------------
FALSE
SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> Disconnected from Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production
With the Partitioning, OLAP, Advanced Analytics and Real Application Testing options
[oracle@personal ~]$ cd ${ORACLE_HOME}/rdbms/lib
[oracle@personal lib]$ make -f ins_rdbms.mk uniaud_on ioracle ORACLE_HOME=$ORACLE_HOME
/usr/bin/ar d /opt/app/oracle/product/12.1.0/dbhome_1/rdbms/lib/libknlopt.a kzanang.o
/usr/bin/ar cr /opt/app/oracle/product/12.1.0/dbhome_1/rdbms/lib/libknlopt.a /opt/app/oracle/product/12.1.0/dbhome_1/rdbms/lib/kzaiang.o
chmod 755 /opt/app/oracle/product/12.1.0/dbhome_1/bin
- Linking Oracle
rm -f /opt/app/oracle/product/12.1.0/dbhome_1/rdbms/lib/oracle
/opt/app/oracle/product/12.1.0/dbhome_1/bin/orald -o /opt/app/oracle/product/12.1.0/dbhome_1/rdbms/lib/oracle -m64 -z noexecstack -Wl,--disable-new-dtags -L/opt/app/oracle/product/12.1.0/dbhome_1/rdbms/lib/ -L/opt/app/oracle/product/12.1.0/dbhome_1/lib/ -L/opt/app/oracle/product/12.1.0/dbhome_1/lib/stubs/ -Wl,-E /opt/app/oracle/product/12.1.0/dbhome_1/rdbms/lib/opimai.o /opt/app/oracle/product/12.1.0/dbhome_1/rdbms/lib/ssoraed.o /opt/app/oracle/product/12.1.0/dbhome_1/rdbms/lib/ttcsoi.o -Wl,--whole-archive -lperfsrv12 -Wl,--no-whole-archive /opt/app/oracle/product/12.1.0/dbhome_1/lib/nautab.o /opt/app/oracle/product/12.1.0/dbhome_1/lib/naeet.o /opt/app/oracle/product/12.1.0/dbhome_1/lib/naect.o /opt/app/oracle/product/12.1.0/dbhome_1/lib/naedhs.o /opt/app/oracle/product/12.1.0/dbhome_1/rdbms/lib/config.o -lserver12 -lodm12 -lcell12 -lnnet12 -lskgxp12 -lsnls12 -lnls12 -lcore12 -lsnls12 -lnls12 -lcore12 -lsnls12 -lnls12 -lxml12 -lcore12 -lunls12 -lsnls12 -lnls12 -lcore12 -lnls12 -lclient12 -lvsn12 -lcommon12 -lgeneric12 -lknlopt `if /usr/bin/ar tv /opt/app/oracle/product/12.1.0/dbhome_1/rdbms/lib/libknlopt.a | grep xsyeolap.o > /dev/null 2>&1 ; then echo "-loraolap12" ; fi` -lskjcx12 -lslax12 -lpls12 -lrt -lplp12 -lserver12 -lclient12 -lvsn12 -lcommon12 -lgeneric12 `if [ -f /opt/app/oracle/product/12.1.0/dbhome_1/lib/libavserver12.a ] ; then echo "-lavserver12" ; else echo "-lavstub12"; fi` `if [ -f /opt/app/oracle/product/12.1.0/dbhome_1/lib/libavclient12.a ] ; then echo "-lavclient12" ; fi` -lknlopt -lslax12 -lpls12 -lrt -lplp12 -ljavavm12 -lserver12 -lwwg `cat /opt/app/oracle/product/12.1.0/dbhome_1/lib/ldflags` -lncrypt12 -lnsgr12 -lnzjs12 -ln12 -lnl12 -lnro12 `cat /opt/app/oracle/product/12.1.0/dbhome_1/lib/ldflags` -lncrypt12 -lnsgr12 -lnzjs12 -ln12 -lnl12 -lnnzst12 -lzt12 -lztkg12 -lmm -lsnls12 -lnls12 -lcore12 -lsnls12 -lnls12 -lcore12 -lsnls12 -lnls12 -lxml12 -lcore12 -lunls12 -lsnls12 -lnls12 -lcore12 -lnls12 -lztkg12 `cat /opt/app/oracle/product/12.1.0/dbhome_1/lib/ldflags` -lncrypt12 -lnsgr12 -lnzjs12 -ln12 -lnl12 -lnro12 `cat /opt/app/oracle/product/12.1.0/dbhome_1/lib/ldflags` -lncrypt12 -lnsgr12 -lnzjs12 -ln12 -lnl12 -lnnzst12 -lzt12 -lztkg12 -lsnls12 -lnls12 -lcore12 -lsnls12 -lnls12 -lcore12 -lsnls12 -lnls12 -lxml12 -lcore12 -lunls12 -lsnls12 -lnls12 -lcore12 -lnls12 `if /usr/bin/ar tv /opt/app/oracle/product/12.1.0/dbhome_1/rdbms/lib/libknlopt.a | grep "kxmnsd.o" > /dev/null 2>&1 ; then echo " " ; else echo "-lordsdo12 -lserver12"; fi` -L/opt/app/oracle/product/12.1.0/dbhome_1/ctx/lib/ -lctxc12 -lctx12 -lzx12 -lgx12 -lctx12 -lzx12 -lgx12 -lordimt12 -lclsra12 -ldbcfg12 -lhasgen12 -lskgxn2 -lnnzst12 -lzt12 -lxml12 -locr12 -locrb12 -locrutl12 -lhasgen12 -lskgxn2 -lnnzst12 -lzt12 -lxml12 -lgeneric12 -loraz -llzopro -lorabz2 -lipp_z -lipp_bz2 -lippdcemerged -lippsemerged -lippdcmerged -lippsmerged -lippcore -lippcpemerged -lippcpmerged -lsnls12 -lnls12 -lcore12 -lsnls12 -lnls12 -lcore12 -lsnls12 -lnls12 -lxml12 -lcore12 -lunls12 -lsnls12 -lnls12 -lcore12 -lnls12 -lsnls12 -lunls12 -lsnls12 -lnls12 -lcore12 -lsnls12 -lnls12 -lcore12 -lsnls12 -lnls12 -lxml12 -lcore12 -lunls12 -lsnls12 -lnls12 -lcore12 -lnls12 -lasmclnt12 -lcommon12 -lcore12 -laio -lons `cat /opt/app/oracle/product/12.1.0/dbhome_1/lib/sysliblist` -Wl,-rpath,/opt/app/oracle/product/12.1.0/dbhome_1/lib -lm `cat /opt/app/oracle/product/12.1.0/dbhome_1/lib/sysliblist` -ldl -lm -L/opt/app/oracle/product/12.1.0/dbhome_1/lib
test ! -f /opt/app/oracle/product/12.1.0/dbhome_1/bin/oracle ||\
mv -f /opt/app/oracle/product/12.1.0/dbhome_1/bin/oracle /opt/app/oracle/product/12.1.0/dbhome_1/bin/oracleO
mv /opt/app/oracle/product/12.1.0/dbhome_1/rdbms/lib/oracle /opt/app/oracle/product/12.1.0/dbhome_1/bin/oracle
chmod 6751 /opt/app/oracle/product/12.1.0/dbhome_1/bin/oracle
[oracle@personal lib]$ lsnrctl start
LSNRCTL for Linux: Version 12.1.0.2.0 - Production on 15-APR-2018 21:40:51
Copyright (c) 1991, 2014, Oracle. All rights reserved.
Starting /opt/app/oracle/product/12.1.0/dbhome_1/bin/tnslsnr: please wait...
TNSLSNR for Linux: Version 12.1.0.2.0 - Production
System parameter file is /opt/app/oracle/product/12.1.0/dbhome_1/network/admin/listener.ora
Log messages written to /opt/app/oracle/diag/tnslsnr/personal/listener/alert/log.xml
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=LISTENER)))
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=personal)(PORT=1521)))
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC1521)))
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=LISTENER)))
STATUS of the LISTENER
------------------------
Alias LISTENER
Version TNSLSNR for Linux: Version 12.1.0.2.0 - Production
Start Date 15-APR-2018 21:40:52
Uptime 0 days 0 hr. 0 min. 0 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Parameter File /opt/app/oracle/product/12.1.0/dbhome_1/network/admin/listener.ora
Listener Log File /opt/app/oracle/diag/tnslsnr/personal/listener/alert/log.xml
Listening Endpoints Summary...
(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=LISTENER)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=personal)(PORT=1521)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC1521)))
The listener supports no services
The command completed successfully
[oracle@personal lib]$ sqlplus / as sysdba
SQL*Plus: Release 12.1.0.2.0 Production on Sun Apr 15 21:41:02 2018
Copyright (c) 1982, 2014, Oracle. All rights reserved.
Connected to an idle instance.
SQL> startup
ORACLE instance started.
Total System Global Area 1543503872 bytes
Fixed Size 2924736 bytes
Variable Size 939528000 bytes
Database Buffers 587202560 bytes
Redo Buffers 13848576 bytes
Database mounted.
Database opened.
SQL> SELECT VALUE FROM V$OPTION WHERE PARAMETER = 'Unified Auditing';
VALUE
----------------------------------------------------------------
TRUE
SQL>
Summary: