Java Modifiers Tutorial

There are 2 types of Modifier in java . Java access modifier and Non access modifier

There are 4 types of java access modifiers

private

default

protected

public

Non access modifiers are static, abstract, volatile, transient etc..

Java private access modifier Example

Hen class

package bird;
 
public class Hen {
 
    private String rice;
 
    public Hen() {
        rice = "eat";
    }
}

Fly class

package flying;
 
import bird.Hen;
 
public class Fly {
    public void top(Hen hen) {
        hen.rice = "fly"; // COMPILE ERROR

    }
}

Error because accessing private members outside the class.

Java default access modifier Example

Wolf class

 package animal;
 
class Wolf {
    public void play() {
     }
}

Person class

package human;
 
import animal.Wolf;
 
public class Person {
    public void hunt() {
        Wolf wolf = new Wolf(); // COMPILE ERROR
    }
}

Error because the Wolf class has default accessibility

Java protected access modifier Example

Person class

package human;
 
import animal.Dog;
 
public class Person {
    public void play() {
        Dog dog = new Dog();
        dog.waveTail(); // COMPILE ERROR!
    }
}

Dog class

package animal;
 
public class Dog {
    protected void waveTail() {
        System.out.print("Waving my tail...");
    }
}

waveTail() has protected access in Dog

Java public access modifier

Dog class

package animal;
 
public class Dog {
    public String name;
 
    public void bark() {
        System.out.print("Gow Gow!");
    }
}

Trainer class

package training;

import animal.Dog;

public class Trainer {
public void teach(Dog dog) {

 dog.name = "Rex";
dog.bark();
}
}

Here, the Dog and Trainer classes are in 2 different packages: animal and training, respectively. Because the Dog class is declared as public, and also its member name field and bark() method, the Trainer class can invoke them: