SQL> SELECT consumer_group FROM dba_rsrc_consumer_groups;

CONSUMER_GROUP
------------------------------
OTHER_GROUPS
DEFAULT_CONSUMER_GROUP
SYS_GROUP
LOW_GROUP
AUTO_TASK_CONSUMER_GROUP

-- Create a job class.
BEGIN
DBMS_SCHEDULER.create_job_class (
job_class_name => 'test_job_class',
resource_consumer_group => 'AUTO_TASK_CONSUMER_GROUP');
END;
/

PL/SQL procedure successfully completed.

SQL> SELECT job_class_name, resource_consumer_group FROM dba_scheduler_job_classes;

JOB_CLASS_NAME RESOURCE_CONSUMER_GROUP
------------------------------ ------------------------------
DEFAULT_JOB_CLASS
AUTO_TASKS_JOB_CLASS AUTO_TASK_CONSUMER_GROUP
TEST_JOB_CLASS AUTO_TASK_CONSUMER_GROUP

--create job

-- Job defined entirely by the CREATE JOB procedure.
DBMS_SCHEDULER.create_job (
job_name => 'test_full_job',
job_type => 'PLSQL_BLOCK',
job_action => 'BEGIN DBMS_STATS.gather_schema_stats(''SCOTT''); END;',
start_date => SYSTIMESTAMP,
repeat_interval => 'freq=hourly; byminute=0',
end_date => NULL,
enabled => TRUE,
comments => 'Job defined entirely by the CREATE JOB procedure.');

DBMS_SCHEDULER.set_attribute (
name => 'test_full_job',
attribute => 'job_class',
value => 'test_job_class');
END;
/

--drop job class

BEGIN
DBMS_SCHEDULER.drop_job_class (
job_class_name => 'test_job_class',
force => TRUE);
END;
/