Execute this SQL editor.
========================
create or replace
PROCEDURE add_job_history2
  (  p_emp_id          job_history.employee_id%type
   , p_start_date      job_history.start_date%type
   , p_end_date        job_history.end_date%type
   , p_job_id          job_history.job_id%type
   , p_department_id   job_history.department_id%type
   )
IS
BEGIN
  INSERT INTO job_history (employee_id, start_date, end_date,
                           job_id, department_id)
    VALUES(p_emp_id, p_start_date, p_end_date, p_job_id, p_department_id);
END add_job_history;
=====================
It gives output:
Executed successfully in 0.293 s, 0 rows affected.
Line 1, column 1

Error code 900, SQL state 42000: ORA-00900: invalid SQL statement

Line 14, column 1

Execution finished after 0.293 s, 1 error(s) occurred.

The problem is SQL executer split this to two commands divided by ';' what is wrong in this case.