third commit

src/Bachler.java

+import org.university.core.Course;
+import org.university.core.Department;
+import org.university.core.Student;
+
+import java.util.ArrayList;
+
+public class Bachler extends Student {
+    public Bachler(String firstName, String lastName, String ID, int joiningYear, Department department, ArrayList<Course> courses) {
+        super(firstName, lastName, ID, joiningYear, department, courses);
+    }
+}

src/Course.java

-public class Course {
-
-    private String title;
-    private String description;
-
-    public String getTitle() {
-        return title;
-    }
-
-    public String getDescription() {
-        return description;
-    }
-}

src/Master.java

-import java.util.ArrayList;
-
-public class Master {
-
-    private ArrayList<Essay> essays;
-
-    public ArrayList<Essay> getEssays() {
-        return essays;
-    }
-}

src/ServiceEmployee.java

-public class ServiceEmployee {
-
-    public int incomeCalculate(){
-
-    }
-}

src/Student.java

-import java.util.ArrayList;
-
-public class Student {
-
-    protected ArrayList<Course> courses;
-
-    public ArrayList<Course> getCourses() {
-        return courses;
-    }
-}

src/AbstarctEmployee.java → src/org/university/core/AbstarctEmployee.java

+package org.university.core;
+
 import java.util.ArrayList;
 
-public class AbstarctEmployee {
+public abstract class AbstarctEmployee extends Person {
 
     protected ArrayList<Payroll> payrolls;
     protected int defPay;
     protected int income;
 
+    public AbstarctEmployee(String firstName, String lastName, String ID, int joiningYear, Department department, int defPay, ArrayList<Payroll> payrolls) {
+        super(firstName, lastName, ID, joiningYear, department);
+        this.defPay = defPay;
+        this.payrolls = payrolls;
+    }
 
     public ArrayList<Payroll> getPayrolls() {
         return this.payrolls;
@@ -15,7 +22,7 @@ public class AbstarctEmployee {
         return defPay;
     }
 
-    public int incomeCalculate(){
+    abstract public int incomeCalculate();
 
-    }
+    abstract public boolean isPromoteable ();
 }

src/org/university/core/Course.java

+package org.university.core;
+
+import java.util.ArrayList;
+
+public class Course {
+
+    private String title;
+    private Teacher instructor;
+    private ArrayList<Student> students = new ArrayList<Student>();
+    private Master teacherAssistance;
+
+
+    public Course(String name, Teacher instructor) {
+        this.title = name;
+        this.instructor = instructor;
+    }
+
+    public String getTitle() {
+        return this.title;
+    }
+
+    public Master getTeacherAssistance() {
+        return this.teacherAssistance;
+    }
+
+    public void setTeacherAssistance(Master teacherAssistance) {
+        this.teacherAssistance = teacherAssistance;
+    }
+
+
+    public Teacher getInstructor() {
+        return this.instructor;
+    }
+
+    public ArrayList<Student> getStudents() {
+        return this.students;
+    }
+
+    public void addStudent(Student student) {
+        this.students.add(student);
+    }
+}

src/Department.java → src/org/university/core/Department.java

+package org.university.core;
+
 import java.util.ArrayList;
 
 public class Department {
@@ -5,6 +7,10 @@ public class Department {
     private ArrayList<Course> courses;
     private String name;
 
+    public Department(String name) {
+        this.name = name;
+    }
+
     public String getName() {
         return name;
     }
@@ -12,4 +18,9 @@ public class Department {
     public ArrayList<Course> getCourses() {
         return courses;
     }
+
+    public void addCourse(Course course) {
+        courses.add(course);
+    }
+
 }

src/Essay.java → src/org/university/core/Essay.java

+package org.university.core;
+
 public class Essay {
 
     private String title;

src/Main.java → src/org/university/core/Main.java

+package org.university.core;
+
 public class Main {
 
     public static void main(String[] args) {

src/org/university/core/Master.java

+package org.university.core;
+
+import java.util.ArrayList;
+
+public class Master extends Student {
+
+    private ArrayList<Essay> essays;
+
+    public Master(String firstName, String lastName, String ID, int joiningYear, Department department, ArrayList<Course> courses, ArrayList<Essay> essays) {
+        super(firstName, lastName, ID, joiningYear, department, courses);
+        this.essays = essays;
+    }
+
+    public ArrayList<Essay> getEssays() {
+        return essays;
+    }
+}

src/Payroll.java → src/org/university/core/Payroll.java

+package org.university.core;
+
 public class Payroll {
 
     private int id;

src/Person.java → src/org/university/core/Person.java

+package org.university.core;
+
 public class Person {
 
     protected String firstName;

src/org/university/core/ServiceEmployee.java

+package org.university.core;
+
+import java.util.ArrayList;
+
+public class ServiceEmployee extends AbstarctEmployee {
+
+    public ServiceEmployee(String firstName, String lastName, String ID, int joiningYear, Department department, int defPay, ArrayList<Payroll> payrolls) {
+        super(firstName, lastName, ID, joiningYear, department, defPay, payrolls);
+    }
+
+    public int incomeCalculate() {
+
+
+    }
+
+    @Override
+    public boolean isPromoteable() {
+        return false;
+    }
+}

src/org/university/core/Student.java

+package org.university.core;
+
+import java.util.ArrayList;
+
+public class Student extends Person {
+
+    protected ArrayList<Course> courses;
+
+    public Student(String firstName, String lastName, String ID, int joiningYear, Department department, ArrayList<Course> courses) {
+        super(firstName, lastName, ID, joiningYear, department);
+        this.courses = courses;
+    }
+
+    public ArrayList<Course> getCourses() {
+        return this.courses;
+    }
+}

src/Teacher.java → src/org/university/core/Teacher.java

+package org.university.core;
+
 import java.util.ArrayList;
 
-public class Teacher {
+public class Teacher extends AbstarctEmployee {
 
     private ArrayList<Course> courses;
 
+    public Teacher(String firstName, String lastName, String ID, int joiningYear, Department department, int defPay, ArrayList<Payroll> payrolls, ArrayList<Course>courses) {
+        super(firstName, lastName, ID, joiningYear, department, defPay, payrolls);
+        this.courses = courses;
+    }
+
     private void addCourse(Course course) {
         this.courses.add(course);
     }
     private void removeCourse(Course course){
         this.courses.remove(course);
     }
+
     public int incomeCalculate(){
 
     }
+
+    @Override
+    public boolean isPromoteable() {
+        return false;
+    }
 }