What is the purpose having final keyword in method parameter? [duplicate]

Question

This question already has answers here:

Why should I use the keyword "final" on a method parameter in Java? (12 answers)

Closed 9 years ago.

I recently saw a method like

public void display(final String toDisplay){

}

I want to know the purpose of final keyword in method parameter.

Answer 1

final variables means you can not change the value.

For example final int x=9; and after that if you change it with x=6; then it will not compile.

So in your case

public void display(final String toDisplay){

}

In this method you are allowing a String argument and after that within that method if you try to change then it will not compile.

Answer 2

suppose your method doing complex calculation so by accidentally you may not change the value of toDisplay variable this is the main reason I can say.

Answer 3

It is to make sure that the implementation will not change the reference.

Answer 4

It simply tells the compiler that this method can not change the thing that parameter points to.