How does the final keyword in Java work

Question

In Java we use final keyword with variables to specify its values are not to be changed. But I see that you can change the value in the constructor / methods of the class. Again, if the variable is static then it is a compilation error.

Answer 1

You are always allowed to initialize a final variable. The compiler makes sure that you can do it only once.

Note that calling methods on an object stored in a final variable has nothing to do with the semantics of final. In other words: final is only about the reference itself, and not about the contents of the referenced object.

Java has no concept of object immutability; this is achieved by carefully designing the object, and is a far-from-trivial endeavor.

Answer 2

A final variable that is created inside the constructor, method or block is known as a local final variable. It must be initialized once where it is created. We have declared a final local variable inside the method.

Answer 3

Final is a keyword that is used to restrict the user in Java programming. Final Keyword in Java is a non-access modifier that is only applicable to a variable, a method, or a class. Java Final keyword has three different uses:
1. To create constants.
2. To prevent inheritance.
3. To prevent methods from being overridden.