Access Modifiers
The access modifiers in java specifies accessibility (scope) of a data member, method, constructor or class.
There are 4 types of java access modifiers:
private access modifier
The private access modifier is accessible only within class.
Simple example of private access modifier
In this example, we have created two classes A and Simple. A class contains private data member and private method. We are accessing these private members from outside the class, so there is compile time error.
class A{
private int data=40;
private void msg(){System.out.println("Hello java");}
}
public class Simple{
public static void main(String args[]){
A obj=new A();
System.out.println(obj.data);//Compile Time Error
obj.msg();//Compile Time Error
}
}
default access modifier
If you don't use any modifier, it is treated as default by default. The default modifier is accessible only within package.
Example of default access modifier
In this example, we have created two packages pack and mypack. We are accessing the A class from outside its package, since A class is not public, so it cannot be accessed from outside the package.
//save by A.java
package pack;
class A{
void msg(){System.out.println("Hello");}
}
//save by B.java
package mypack;
import pack.*;
class B{
public static void main(String args[]){
A obj = new A();//Compile Time Error
obj.msg();//Compile Time Error
}
} In the above example, the scope of class A and its method msg() is default so it cannot be accessed from outside the package.
protected access modifier
The protected access modifier is accessible within package and outside the package but through inheritance only.
The protected access modifier can be applied on the data member, method and constructor. It can't be applied on the class.
public access modifier
The public access modifier is accessible everywhere. It has the widest scope among all other modifiers.
Example of public access modifier//save by A.java
package pack;
public class A{
public void msg(){System.out.println("Hello");}
} //save by B.java
package mypack;
import pack.*;
class B{
public static void main(String args[]){
A obj = new A();
obj.msg();
}
}
Output:Hello
There are 4 types of java access modifiers:
- private
- default
- protected
- public
private access modifier
The private access modifier is accessible only within class.
Simple example of private access modifier
In this example, we have created two classes A and Simple. A class contains private data member and private method. We are accessing these private members from outside the class, so there is compile time error.
class A{
private int data=40;
private void msg(){System.out.println("Hello java");}
}
public class Simple{
public static void main(String args[]){
A obj=new A();
System.out.println(obj.data);//Compile Time Error
obj.msg();//Compile Time Error
}
}
default access modifier
If you don't use any modifier, it is treated as default by default. The default modifier is accessible only within package.
Example of default access modifier
In this example, we have created two packages pack and mypack. We are accessing the A class from outside its package, since A class is not public, so it cannot be accessed from outside the package.
//save by A.java
package pack;
class A{
void msg(){System.out.println("Hello");}
}
//save by B.java
package mypack;
import pack.*;
class B{
public static void main(String args[]){
A obj = new A();//Compile Time Error
obj.msg();//Compile Time Error
}
} In the above example, the scope of class A and its method msg() is default so it cannot be accessed from outside the package.
protected access modifier
The protected access modifier is accessible within package and outside the package but through inheritance only.
The protected access modifier can be applied on the data member, method and constructor. It can't be applied on the class.
public access modifier
The public access modifier is accessible everywhere. It has the widest scope among all other modifiers.
Example of public access modifier//save by A.java
package pack;
public class A{
public void msg(){System.out.println("Hello");}
} //save by B.java
package mypack;
import pack.*;
class B{
public static void main(String args[]){
A obj = new A();
obj.msg();
}
}
Output:Hello