Lesson: Class and Object

 Bir paketin icinde eyni adli cemi 1 eded class duzelde bilerik.

package org.example;

public class Car {
    public String model;
    public String color;
    public int year;
    public static String manufacturer;

    public static void staticMethod() {
        System.out.println("This is static method");
    }

    public void nonStaticMethod() {
        System.out.println("This is non static method");
        manufacturer = "Mercedes";
    }
}

Car.manufacturer = "General Motors";

System.out.println(Car.manufacturer);

Car car = new Car();
car.nonStaticMethod();
System.out.println(car.manufacturer);

- Weird behaviour

Car c = null;
       c.manufacturer = "Cadillac";
//       c.model = "Island";
        System.out.println(c.manufacturer);
//        System.out.println(c.model);

- Referansin qirilmasi

Car one = new Car();
one.model = "Toyota";

one = new Car();
one.model = "Mercedes";
System.out.println(one.model);

- Biz eyni vaxtda klasin icinde eyni adli hem static hem de non static field elan ede bilmerik. Cunki 

obyekden static fielde cata bilerik. Eger elan ede bilsek o zaman qariwiqliq yaranar.

- Stack Overflow xetasi nedir?

package org.example;

public class Main {
    public static void main(String[] args) {
        method1();
    }

    public static void method1() {
        System.out.println("method1");
        method2();
    }

    public static void method2() {
        System.out.println("method2");
        method1();
    }
}

- Pass by value and pass by reference difference

package org.example;

public class Main {
    public static void main(String[] args) {
        int k = 5;
        foo(k);
        System.out.println(k);
    }

    public static void foo(int a) {
        a = 10;
    }
}

package org.example;

public class Main {
    public static void main(String[] args) {
        Car c = new Car();
        c.model = "Mercedes";
        foo(c);
        System.out.println(c.model);
    }

    public static void foo(Car car) {
        car.model = "Honda";
    }
}

package org.example;

public class Main {
    public static void main(String[] args) {
        char[] el = {'a'};
        foo(el);
        System.out.println(el);
    }

    public static void foo(char[] chars) {
        chars[0] = 'b';
    }
}

-

package org.example;

public class Main {
    public static void main(String[] args) {
        Car one = new Car();

        Car two = foo(one);

        System.out.println(one.model);
        System.out.println(two.model);
    }

    public static Car foo(Car car) {
        car.model = "BMW";
        return car;
    }
}

-- interesting situation:

package org.example2;

public class Main {
    Integer a;
    public static void main(String[] args) {
        new Main().foo("test");
    }
    
    public void foo(String s) {
        Integer i;
        System.out.println(i);
        System.out.println(a);
    }
}

- Access modifiers (public, private, default, protected)

Getter and Setter anlayishi. Encapsulation nedir?