What is the purpose having final keyword in method parameter?

Question

I recently saw a method like

public void display(final String toDisplay){

}

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

BTW: I have already searched it on SO, so please don't downvote; I know its a duplicate. I know this question has been asked many times and trust I went through all of them but did not understand any of the answers. Please while answering assume that you are talking to a beginner.

Wht exactly u didn't understand? bcoz if its again explained, it might not be wht u want. — Lokesh, Apr 01 '14 at 03:49
so you can have a Fantasy class and declare it as final Fantasy — Mc Kevin, Apr 01 '14 at 04:00
@Lokesh The language that the answers I went had was very tough to understand. — Nick Div, Apr 01 '14 at 17:09

score 4 · Accepted Answer · edited Apr 24 '14 at 21:09

4

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.

edited Apr 24 '14 at 21:09

Kevin Panko

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answered Apr 01 '14 at 03:52

SpringLearner

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Thanks that was simple enough. – Nick Div Apr 01 '14 at 17:08
what is the point of this? any "changes" would be to the locally scoped reference, and not to the actual object, so clients cannot possibly see any difference, right? – sara May 01 '16 at 16:15

score 2 · Answer 2 · answered Apr 01 '14 at 04:52

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.

answered Apr 01 '14 at 04:52

Sanjay Rabari

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Thanks a lot. I get your answer – Nick Div Apr 01 '14 at 17:08

score 1 · Answer 3 · answered Apr 01 '14 at 03:49

1

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

answered Apr 01 '14 at 03:49

Vincent Cantin

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score 0 · Answer 4 · answered Apr 01 '14 at 03:50

0

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

answered Apr 01 '14 at 03:50

deiga

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What is the purpose having final keyword in method parameter?

4 Answers4