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final parameter

Posted on 2012-03-15
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Last Modified: 2012-03-16
Does declaring a parameter as final serve a purpose?

public void myMethod (final int x) {
   ....
}

Obviously, x is already passed by value, so the value can't be changed.
If I understand correctly, I copy of x is made for use in the method, and if its not already final by default, declaring it so might make the copy take less space.
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Question by:allelopath
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by:Kyle Abrahams
Kyle Abrahams earned 167 total points
ID: 37724716
http://www.jguru.com/faq/view.jsp?EID=19556

Says the param won't be modified.
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gudii9 earned 167 total points
ID: 37724978
Sometimes its nice to be explicit(for readability) that the variable doesn't change. Here's a simple example where using final can save some possible headaches

public void setTest(String test) {
    test = test;
}

if you forget the 'this' keyword on a setter the variable you want to set doesn't get set. However if you used the final keyword on the parameter then the bug would be caught at compile time.



http://stackoverflow.com/questions/500508/why-should-i-use-the-keyword-final-on-a-method-parameter-in-java
http://stackoverflow.com/questions/316352/why-would-one-mark-local-variables-and-method-parameters-as-final-in-java
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by:gurvinder372
gurvinder372 earned 166 total points
ID: 37724980
it cannot be modified for the calling method, but it can be modified in the method in which it is going as a parameter. Making it 'final' make it constant in a method in which it has gone as a parameter also.
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