Waht is final keywords in java

In Java, the `final` keyword is a modifier that can be applied to various elements, including classes, methods, and variables. Its usage implies that the declared entity is not allowed to be further modified or extended.

1. **Final Variables:**
   - When applied to a variable, it means that the variable's value cannot be changed once it has been assigned.

     ```java
     final int constantValue = 10;
     // constantValue = 20; // Error: cannot assign a value to a final variable
     ```

2. **Final Methods:**
   - When applied to a method, it means that the method cannot be overridden by subclasses.

     ```java
     class Parent {
         final void finalMethod() {
             //Some implementation< /span> }
         }

     class Child extends Parent {
         // Error: Cannot override the final method from Parent
         // void finalMethod() { }     }     `` `
 

3. **Final Classes:**
   - When applied to a class, it means that the class cannot be extended. In other words, it cannot be used as a superclass.

     ```java
     final class FinalClass {
         //Some implementation
     }

     // Error: Cannot extend final class FinalClass
     // class SubClass extends FinalClass { }
     ```

4. **Final Parameters:**
   - When applied to a method parameter, it means that the parameter cannot be reassigned within the method.

     ```java
     void someMethod(final int parameter) {
         //Error: Cannot assign a value to a final variable (parameter)
         // parameter = 5;
     }
     ```

Using the `final` keyword has several benefits, including increased code safety, optimization opportunities for the compiler, and enhanced readability by signaling the developer's intent to other programmers.