Error:

ORA-29548: Java system class reported: release of Java system classes in the database (12.1.0.2.0 1.6) does not match that of the oracle executable (12.1.0.2.180717 1.6)

The error is due to java.

Solution:

Connect as sys and run below

SQL> show user
USER is "SYS"
SQL> @?/javavm/install/update_javavm_db.sql

SQL> SET FEEDBACK 1
SQL> SET NUMWIDTH 10
SQL> SET LINESIZE 80
SQL> SET TRIMSPOOL ON
SQL> SET TAB OFF
SQL> SET PAGESIZE 100
SQL>
SQL> alter session set "_ORACLE_SCRIPT"=true;

Session altered.

SQL>
SQL> -- If Java is installed, do CJS.
SQL>
SQL> -- If CJS can deal with the SROs inconsistent with the new JDK,
SQL> -- the drop_sros() call here can be removed.
SQL> call initjvmaux.drop_sros();

Call completed.

SQL>
SQL> create or replace java system;
  2  /

Java created.

SQL>
SQL> update dependency$
  2    set p_timestamp=(select stime from obj$ where obj#=p_obj#)
  3    where (select stime from obj$ where obj#=p_obj#)!=p_timestamp and
  4          (select type# from obj$ where obj#=p_obj#)=29  and
  5          (select owner# from obj$ where obj#=p_obj#)=0;

0 rows updated.

SQL>
SQL> commit;

Commit complete.

SQL>
SQL> alter session set "_ORACLE_SCRIPT"=false;

Session altered.

Verify and check the java now:

SQL> select dbms_java.get_jdk_version() from dual;

DBMS_JAVA.GET_JDK_VERSION()
--------------------------------------------------------------------------------
1.6.0_201

1 row selected.