What is the significance of the 'final' keyword in Java?

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Ashutosh Kumar Verma · Answer

Final Keyword in Java
The key word ‘end’ is used to indicate that something cannot always be changed. It varies in importance according to its use:
Final Variablesand 
When applied to a variable, it means that the value of the variable cannot be changed once it is initialized.
Syntax-
final int x = 10;
// x = 20; // Compilation error: cannot assign a value to final variable x
and 
Final Methodsand 
Used in a method, it means that subclasses cannot be placed on the method.
Syntax-
class Parent {
   final void display() {
       System.out.println("Parent's display method");
   }
}
class Child extends Parent {
   // Compilation error: Cannot override the final method from Parent
    void display() {
       System.out.println("Child's display method");
    }
}
and 
Final Classesand 
When applied to a class, it means that the class cannot be parsed (i.e. no other class can inherit from it).
Syntax-
final class FinalClass {
   // Class implementation
}
// Compilation error: Cannot inherit from final FinalClass
// class SubClass extends FinalClass {
//     // Class implementation
// }
Final Parametersand 
When applied to a method parameter, it indicates that the parameter cannot be changed in the method.
Syntax-and 
void printValue(final int num) {
   // num = 20; // Compilation error: cannot assign a value to final parameter num
   System.out.println("Value: " + num);
}
The 'final' keyword ensures immutability, prevents method execution, prohibits subclassing, or forces method parameters to remain unchanged within a method This provides code reliability, security, and performance up in Java programs.
and 
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Also, Read: 
What is a HashMap and how does it work?

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What is the significance of the 'final' keyword in Java?

Ashutosh Kumar Verma

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Final Keyword in Java

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