Class and Objects

 package main;

public class Car {
    String make;
    String model;
    String year;
    int speed;
    int distance;

    Person owner;

    public void go(int newDistance) {
        distance += newDistance;
    }

    public void accelerate(int newSpeed) {
        speed += newSpeed;
    }

    public void stop() {
        speed = 0;
    }

    public String getInfo() {
        String info = "Car info: " + year + " " + make + " " + model + ". Distance: " +
                distance + " km. and traveling at " + speed + " kmph.";
        if (owner != null)
            info += " and its owner is " + owner.firstName + " " + owner.lastName;
        else
            info += " and does not have an owner";
        return info;
    }
}

package main;

public class Person {
    String tckn;
    String firstName;
    String lastName;

    Car vehicle;

    public String getInfo() {
        String info = "Person info: " + tckn + " " + firstName + " " + lastName;
        if(vehicle != null)
            info += " and has a car: " + vehicle.getInfo();
        else
            info += " and has no car";
        return info;
    }
}
package main;

public class Main {
    public static void main(String[] args) {
        Person zeynep = new Person();
        zeynep.tckn = "1";
        zeynep.firstName = "Zeynep";
        zeynep.lastName = "Kaya";

        Car mercedes = new Car();
        mercedes.make = "Mercedes";
        mercedes.model = "E200";
        mercedes.year = "2011";
        mercedes.speed = 80;
        mercedes.distance = 30_000;

        mercedes.owner = zeynep;
        zeynep.vehicle = mercedes;

        System.out.println(mercedes.getInfo());
        System.out.println(zeynep.getInfo());
    }
}





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package university;

import java.util.Date;

public class Course {
    String code;
    String name;
    Department department;
    Professor teacher;
    Student[] students;
    String[] days;
    Date time;
}
package university;

public class Department {
    String name;
    Professor head;
    Course[] courses;
    Student[] students;
}
package university;

public class Professor {
    String no;
    String name;
    String dob;
    String rank;
    Department department;
    Student[] advisee;
    Course[] coursesGiven;
}
package university;

public class Student {
    String no;
    String name;
    String dob;
    Department department;
    Professor advisor;
    Course[] coursesTaken;
}
package university;

public class Test {
    public static void main(String[] args) {
        Department department1 = new Department();
        department1.name = "Software Engineering";

        Professor professor1 = new Professor();
        professor1.name = "Ahmet Arslan";

        Course course1 = new Course();
        course1.name = "Introduction to Software Engineering";

        Student student1 = new Student();
        student1.name = "Akin Kaldiroglu";

        department1.head = professor1;
        professor1.department = department1;

        course1.department = department1;
        department1.courses = new Course[100];
        department1.courses[0] = course1;

        course1.teacher = professor1;
        professor1.coursesGiven = new Course[5];
        professor1.coursesGiven[0] = course1;

        professor1.advisee = new Student[10];
        professor1.advisee[0] = student1;
        student1.advisor = professor1;

        student1.coursesTaken = new Course[7];
        student1.coursesTaken[0] = course1;

        course1.students = new Student[100];
        course1.students[0] = student1;
    }
}




Methods.
Methods(behaviours) - obyektin responsibility yerine yetiren funksiyalardir. Metodlar yalniz
klasin icinde tanimlana biler. 
Metodun hisseleri: Metod 6 hisseden ibaretdir
<modifier>* <return type> <name> (<Parameter>*) throws <exception>* { <statement>*}