final commit

src/org/university/core/Professor.java

@@ -4,6 +4,7 @@ import java.util.ArrayList;
 
 public class Professor extends AbstractEmployee
 {
+    private double income = 0;
     private ArrayList<Course> courses;
     private ArrayList<Article> articles;
     private String group;
@@ -12,6 +13,20 @@ public class Professor extends AbstractEmployee
                      Department department, String position, double basicIncome, String group) {
         super(firstName, lastName, ID, joiningYear, department, position, basicIncome);
         this.group = group;
+        this.income = 0;
+    }
+
+
+    public void income(Professor professor){
+        income = (professor.articles.size()*1000) + basicIncome;
+    }
+
+    public void setIncome(double income) {
+        this.income = income;
+    }
+
+    public double getIncome() {
+        return income;
     }
 
     public void addArticle(Article a){

src/org/university/core/ServiceEmployee.java

@@ -4,14 +4,32 @@ import java.util.Date;
 
 public class ServiceEmployee extends AbstractEmployee
 {
+    double income = 0;
+    int additionalHour = 0;
     public ServiceEmployee(String firstName, String lastName, String ID, int joiningYear, Department department, String position, double basicIncome) {
         super(firstName, lastName, ID, joiningYear, department, position, basicIncome);
+        this.income = 0;
     }
     int passedDays = 0;
 
     public void setPassedDays(int passedDays) {
         this.passedDays++;
     }
+    public void income(ServiceEmployee serviceEmployee){
+        income = ( additionalHour*500) + basicIncome;
+    }
+
+    public double getIncome() {
+        return income;
+    }
+
+    public void setIncome(double income) {
+        this.income = income;
+    }
+
+    public void setAdditionalHour(int additionalHour) {
+        this.additionalHour = additionalHour;
+    }
 
     @Override
     public boolean isPromotable() {