1-dars Java nima? Java dasturlash tili va platforma

interface Printable{

void print();

}

interface Showable{

void show();

}

class A implements Printable,Showable{

public void print(){System.out.println("Salom");}

public void show(){System.out.println("Hush kelibsiz");}

public static void main(String args[]){

A obj = new A();

obj.print();

obj.show();

}

}

Quyidagi misolda klass interfeysdan foydalanadi, interfeys esa boshqa interfeysdan nasl oladi:

interface Printable{

void print();

}

interface Showable extends Printable{

void show();

}

class A implements Showable{

public void print(){System.out.println("Salom");}

public void show(){System.out.println("Hush kelibsiz");}

public static void main(String args[]){

A obj = new A();

obj.print();

obj.show();

}

}

Shunindek, bir interfeys tarkibida boshqa bir interfeys bo'lishi ham mumkin:

interface Xat {

void xatKeldi();

interface xatHabar{

void xatHabarKeldi();

}

}

Abstrakt klass va interfeys o'rtasidagi farqlar

Abstrakt klass	Interfeys
Abstrakt klassda abstrakt va abstrakt bo'lmagan funksiyalar bo'ladi	Interfeysda faqat abstrakt funksiyalar bo'ladi
Classlar faqat bitta abstrakt klassdan meros olishi mumkin	Classlar bir nechta interfeyslardan meros olishi mumkin
Abstrakt klasslarda final, non-final static va non-static bo'lgan o'zgaruvchilar bo'lishi mumkin	Interfeysda esa faqat final va static o'zgaruvchilar bo'ladi
Abstrakt klaslarda static funksiyalar, main funksiyalar va konstruktorlar yaratish mumkin	Interfeysda esa static funksiyalar, main funksiyalar va konstruktorlar yaratib bo'lmaydi

Interfeys va abstrakt klasslarga misol:

//interface da 4ta method yaratilyapti

interface A {

void a(); abstract

void b();

void c();

void d();

}

// B abstrakt klassi yaratilyapti va A interfeysdan foydalanilyapti

abstract class B implements A{

public void c() {System.out.println("Men c man ");}

}

class M extends B{

public void a(){System.out.println("Men a man ");}

public void b(){System.out.println("Men d man ");}

public void d(){System.out.println("Men d man ");}

}

class Test5{

public static void main(String args[]){

A a=new M();

a.a();

a.b();

a.c();

a.d();

}

}

Natija :

Men a man

Men b man

Men d man

Men c man

21-dars - Javada Collection (To’plam).



Javada to'plamlar(collection'lar) framework bo'lib, u o'zida obyektlarni saqlaydi.

To'plamlarda barcha jarayonlar ( saralash, qidirish, yozish, o'chirish va h.k lar)ni oson amalga oshirish mumkin.

To'plamlar bir necha interface'lardan tashkil topgan. Ular ( Set, List, Queue, Deque etc.) va klass'lar (ArrayList, Vector, LinkedList, PriorityQueue, HashSet, LinkedHashSet, TreeSet va h.k).

To'plamlar obyektning alohida ko'rinishi.