Shoukd the 'final' keyword should be used on all input parameters?

Question

In my very limited experience as a java programmer have never seen this done any where. Except in the java.lang.Math class which has a final variable, of type double, called PI. As pi is not a value that should change during the execution of a program, though this is not passed in as a parameter.
However, on a new project, a co-worker is proposing the use of the 'final' keyword on all input parameters as a standard. He has about 5 years experience of maintaining java systems and is putting this suggestion forward as in the past people have overwritten values passed in as parameters causing confusion. Personally I don't see why this is such a major issue if one reads the code of the called programs.
I would be grateful if anyone has seen this done before, or has any views on the advantages or disadvantages of this.
Thanks in advance,
LS

Answer 1

Lord_Sidcup wrote:
In my very limited experience as a java programmer have never seen this done any where. Except in the java.lang.Math class which has a final variable, of type double, called PI. As pi is not a value that should change during the execution of a program, though this is not passed in as a parameter.
I'm sorry, but this point is irrelevant. There are lots of final fields (but not that many final parameters) in Java, BTW. Every field you declare in an interface is automatically final, for example.
However, on a new project, a co-worker is proposing the use of the 'final' keyword on all input parameters as a standard. He has about 5 years experience of maintaining java systems and is putting this suggestion forward as in the past people have overwritten values passed in as parameters causing confusion. Personally I don't see why this is such a major issue if one reads the code of the called programs.
IMHO, it's definately not a major issue. It is simply being restrictive, to be restrictive. The guy may have "five years experience", but he sounds lazy, to me. Besides, the first thing I would do in that case (if final were the default), would be something like this:
public void myMethod (final String a, final int b) {
  String myA = a;
  String myB = b;
}And now, what has he won by making it final? It simply added some up front work for some people, with no real added value. Also, if I had to retroactively change my code, I would change it as follows:
//Original Code
public void myMethod (String myA, int myB) {
  String myA = a;
  String myB = b;
// New code
public void myMethod (final String a, final int b) {
  String myA = a;
  String myB = b;
}That way, you wouldn't even have to worry about changing anything else about your method, as the variables actually used in the rest of the body will remain the same.
I would be grateful if anyone has seen this done before, or has any views on the advantages or disadvantages of this.The only thing declaring the parameter final does, is it prevents you from assigning a new value to the variable. The instance that parameter references (as long as it is not immutable to begin with) can still be manipulated. I.E. except in some very narrow, and specific, cases, no value added, simply a restriction that exists to be restrictive.
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Thanks in advance,
LSEdit: And man, am I slow and long-winded.