What Are Access And Non-Access Modifiers In Java?

Types of modifiers in java.
1- Access Modifier
2- Non-Access Modifier

The visibility of a class, method, constructor, and variable is controlled by access modifiers.
Whereas non-access modifiers are used to provide other functionalities like synchronizing 
a method or block, restricting the serialization of a variable, etc.

Access Modifier- 

Types of access modifier in java-
1-Private
2-Default
3-Protected
4-Public
Private Access Modifier-
Private access modifiers are basically used before method, constructor, and variable.
Private access modifiers can not be used with class and interface. It can be used with the
class when the class in the inner class i.e. class inside another class. Private is the most
restricted level of access.
Important Points About access Modifier-
1-The class in which constructor is declared as private, the object can not be created for
that object.
2-The variable which is declared as private can be accessed using the getter method only.

Example-
package Java_Test;
//class with private variable
class PrivateModifier {
 private int a = 10;
 public int getA() {
  return a;
 }
 public void setA(int a) {
  this.a = a;
 }
}
public class AccessModifiers {
 public static void main(String[] args) {
  PrivateModifier pm = new PrivateModifier();
  System.out.println(pm.getA());
 }
}

Default Access Modifier-
Default access modifiers are basically used before method, constructor, and
variable(If we are not declaring any modifier then it is considered as default access modifier). If we declare any method, constructor or variable as default then it will be accessed from any class within the package.

Protected Access Modifier-
Protected access modifiers are basically used before method, constructor, and variable.
Protected can not be used with the class. If we declare any method, constructor or variable
as protected then it will be accessed from any class within the package and outside the
package through child class.

Public Access Modifier-
A public access modifier is accessible anywhere.

Non Access Modifier- 

There are various non-access modifiers in java. They are used to provide some information
to JVM.
1-final
2-static
3-synchronized
4-abstract
5-transient

final-
It can be used with class, variable, and method.
  • The class which is declared as final can not be inherited.
  • The method which is declared as final can not be overridden.
  • The variable which is declared as final can not be changed once assigned.
static- 
It can be used with block, variable and method and nested class.
  • When a variable is declared as static then it is initialized when class is loaded. 
  • The static variable gets memory only once at the time of class loading.
  • The method which is declared as static can be called directly with the class name.
synchronized- 
The synchronized keyword is used to control the access of multiple threads to any
shared resource.
abstract-
  • The class has at least one unimplemented method(not mandatory) and declared as abstract is known as abstract class.
  • An abstract class is used to achieve abstraction.
transient- 
  • Java transient keyword is used in serialization. 
  • The data member declared as transient will not be serialized.