Modifiers-

Definition-

These are the keywords which  modifies properties of classes and fields.

Types of modifiers-

1- Access modifiers
2-Non-access modifiers

1-Access modifier-

Modifies accessibility of   classes and fields.

-Controls visibility.

(i)Private    – only within class

(ii)Default   – only within package.

(iii)Protected  – within package and outside the package using inheritance

(iv)Public        – everywhere

Note- classes can’t be private and protected.
Note- Local variables can’t have any access modifier

code samples are here

1- Program to demonstrate access modifiers on variables

i- Program for class ExUsingVar

package AccessModifiers8;
public class ExUsingVar {
public int a=10;
private int b=20;
protected int c=30;
int d=40;

public static void main(String[] args) {
ExUsingVar e1 =new ExUsingVar();
System.out.println(e1.a);
System.out.println(e1.b);
System.out.println(e1.c);
System.out.println(e1.d);
}
}


ii-Program for class ExUsingVar1

package AccessModifiers8;
public class ExUsingVar1 {

public static void main(String[] args) {
ExUsingVar e1 =new ExUsingVar();
System.out.println(e1.a);
System.out.println(e1.b);
System.out.println(e1.c);
System.out.println(e1.d);
}
}


iii-Program to show ExUsingVar3

package AccessModifiers8_1;
import AccessModifiers8.ExUsingVar;

public class ExUsingVar3 {

public static void main(String[] args) {
ExUsingVar e1 =new ExUsingVar();
System.out.println(e1.a);
 System.out.println(e1.b);
 System.out.println(e1.c);
 System.out.println(e1.d);
}

}


2-Non Access Modifiers-  (Final,Static,abstract,Transient,Synchronized,Volatile)
1-Final- 
used to restrict the user.
(a)final variable  –
can’t change the value

(b) final method –
can’t override

(c) final class–
can’t inherit

2-Static-
-static belongs to class rather than objects.

(a) static variable

-gets memory only once at the time of class loading.

-used to refer the common property of all objects
(b) static method

– can be invoked without an instance/object

-can access static variable
(c) static nested Class

-can access static data members of outer class
-object is created in scope of outer class
(d) static block

– executes even before main method

-used to initialize static data members

3- Abstract –
-Used in abstraction(oops concept)

-can be applied on-

a- Abstract class

 b- Abstract method
4-Transient-
– prevents serialization of value.(Io package concept)

-only for variable
5-Synchronized-(multi-threading concept)
-prevents sharing by more than one threads at a time

– can be

a- synchronized method

 b- synchronized block
6-Volatile-(multi-threading concept)
– Allows modification at run-time.

– only for variable

			

			
			

        
    
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