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 Non Access Modifiers
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
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
Synchronized methods can be accessed by only one thread at a time.
Native Non Access Modifier
Native methods indicate that the method is implemented on a platform-dependent code.
Strictfp Non-Access Modifier
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.
- 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.