Modifiers are
keywords that you add to those definitions to change their meanings.
There are two types
of modifiers in java: access modifiers and non-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:
1. private
2. default
3. protected
4. public
1. private:
private modifiers access only within class. If we try access private
modifiers outside of class ,it produce compilation error. We There is
two class user and test.User class have private variable and
methods. If we try access private data out side of class then it
gives error.
package
com.javamodifier;
class
User {
private
String name
="java";
private
void
display(){
System.out.println("
name of user is ="+
name);
}
}
public
class
Test{
User user = new
User();
System.out.println(
user.name);
//compilation
error
user.display()
////compilation
error
}
}
How we can access
private data outside class?
For this see public
modifiers . Public modifies explain below in this post.
2 Default :
Default
has scope only inside the same package. If we try access default
modifiers outside of class , it gives error.
There is two
classes Demo and User in different packages.
package
com.javamodifier;
import
com.javatest.User;
public
class
Demo {
public
static
void
main(String[] args) {
User
user = new
User();
System.out.println(user.name);//
CE
}
}
package
com.javatest;
public
class
User {
String
name
;
public
void
display(){
System.out.println("name
of user ="+name);
}
}
3. protected :
Protected has scope within the package and all sub classes. In this
Example We access Student's protected method by inheritance.
package
com.javamodifier;
import
com.javatest.Student;
public
class
Demo extends
Student
{
public
static
void
main(String[] args) {
Student student = new
Student();
student.print();
}
}
package
com.javatest;
public
class
Student {
protected
void
print(){
System.out.println("
Student Called");
}
}
Output:
Studnet Called
4. Public:
Public
scope is visible everywhere. In previous examples we can access print
method of student class without inherintance ,if it declare as
public.
package
com.javamodifier;
import
com.javatest.Student;
public
class
Demo {
public
static
void
main(String[] args) {
Student student = new
Student();
student.print();
}
}
package
com.javatest;
public
class
Student {
public
void
print(){
System.out.println("
Student Called");
}
}
How to Access
Private Modifiers Outside Class:
We can access
private modifiers outside class using public method of this
class(withoout using inherintance). Below we give example. Emp class
have private data mamber empId and private method diplaySalary. These
private modifiers we access throw public accessEmp() method.
package
com.javamodifier;
public
class
MainTest {
public
static
void
main(String[] args) {
Emp
emp = new
Emp();
emp.AccessEmp();
}
}
class
Emp{
private
int
empId=10;
private
void
displaySalary(){
System.out.println("salary
is = 10000");
}
public
void
AccessEmp(){
System.out.println("Emp
id is ="+empId);
displaySalary();
}
}
Output:
Emp
id is =10
salary
is = 10000
Non Access Modifiers:
There is some non-access modifiers of java.
The static modifier for creating class methods and variables
The final modifier for finalizing the implementations of classes, methods, and variables.
The abstract modifier for creating abstract classes and methods.
The synchronized and volatile modifiers, which are used for threads.
