Core Java

Non Access Modifiers in Java

Access modifiers provide a mechanism for Access Control and different access modifiers can be used to achieve different accessibility. But Non-Access Modifiers have nothing to do with accessibility. But it is used to determine specific characteristics of class/variable/methods etc.

Below are the 7 Non Access Modifiers available in Java.

  • Final
  • Abstract
  • Static
  • Strictfp
  • Native
  • Synchronized
  • Transient

Final Non Access Modifiers

Keyword

final

Applicability:

  1. Class
  2. Method
  3. Instance Variable
  4. Local Variable
  5. Method arguments

Final Class :

A class, when set to final, cannot be extended by any other class.

Example: A String Class in java.lang package

Final Method :

A method, when set to final, cannot be overridden by any subclass.

Final Variable :

When a variable is set to final, its value cannot be changed. The final variables are like constants.

Example : public static final int i = 10;


Abstract Non-Access Modifier

Keyword:

  • abstract

Applicability:

  1. Class
  2. Method

Abstract Class:

An Abstract class can have abstract methods. If a class has an abstract method, the class becomes an abstract class. A class can also be an abstract class without having any abstract methods in it.

Abstract Method :

Abstract methods are those methods that do not have a body but only a signature.

Example : public abstract void method();

Synchronized Non-Access Modifier

keyword

synchronized

Applicability

  1. Method

Synchronized Method

Synchronized methods can be accessed by only one thread at a time.

Native Non Access Modifier

Applicability

  1. Method

Native Method

Native methods indicate that the method is implemented on a platform-dependent code.

Strictfp Non-Access Modifier

Applicability

  1. Class
  2. Method

Strictfp Class / Method

Strictfp non-access modifier forces floating-point or floating-point operation to adhere to IEEE 754 standard.

Note*: Strictfp non-access modifier cannot be applied on a variable.

Cheatsheet

  • Non Access Modifiers available in Java are Static, final, abstract, synchronized & Volatile
  • Static keyword can be applied to Variables & Methods.
  • Static Variables are those variables that are not associated with any instance but are associated with the class, which means all instances will access the same single copy of the variable.
  • Local variables can not be declared as static.
  • Static keyword can also be applied to Methods. They will work for all the instances and they will not be dependent on instance creation.
  • A final modifier can be applied to methods and variables.
  • Final is the only modifier that will be available to the local variable.
  • Once declared as the final, the value of the variable can not be changed.
  • A final variable doesn’t get default value as opposed to instance variable coz value can’t be changed once assigned.
  • A final method cannot be overridden.
Author

32 thoughts

  1. Hi Gautham,
    Thank you for such a great explanation, It’s really helpful for a person like me who is just started steps in Java World.

    Extending to your info, would you be able to provide me the real-time scenarios.
    1. When do we need to go for abstract and why?
    2. When do we need to go for strictfp, naive and static and why?

    1. Hi Ram,

      Abstract classes are used when you want subclasses to follow some rules about the method and also you want to provide the default implementation of some methods. Though in Latest versions of Java, this is not a valid scenario, coz now interface can also have a default method but there are things which can be done with abstract and not interface, So in those cases, it makes sense to use abstract.

      I have never used strictfp and naive for myself, so can’t give an example. But the static is a very frequently used keyword. It will be used when you want variable to be class level and not object level. A simple example would be if you want to have an int variable which should be used to count the number of times object of the class has been created. In that case, you will use a static variable to maintain the number.


      public class test123 {
      static int i;

      test123(){
      i++;
      System.out.println("No of times object created"+i);
      }
      public static void main(String[] args) {
      test123 t1 = new test123();
      test123 t2 = new test123();
      test123 t3 = new test123();

      }
      }

      Hope it help.

      Regards

  2. Hi.
    Can you clear my below doubt?
    In the cheat sheet mentioned above there are 2 points which is troubling me.
    1. Local variables can not be declared as Static.
    2. Final is the only modifier which will be available to the local variable.
    But in the previous page regarding static and final explanation it is said that static MUST be used when final keyword is used.
    Can anyone tell me which statement is right?

    1. Hi Karthik,

      Could you please let me know where it is written that static must be used when final keyword is used.
      As for as first 2 points are concerned they are valid in terms of Local Variable. And another statement is about Instance Variable. Though it is not a rule to use static with final instance variable. But it does make sense that final variable should be made static. Coz this variable can not be changed.

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