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Thread: How to protect a parameter beeing modified

  1. #1
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    Default How to protect a parameter beeing modified

    Hi,

    I'm a total beginner with Java - coming from C++
    In the code snippet below, I want to protect the parameter 'V" in method display
    from beeing modified. How can this be achieved (the attribute 'final" doesn't seem to work).
    Many thanks for a hint,
    Helmut.

    class Test {
    public static void main(String[] args) {
    int[] A = new int[3];
    for (int i=0; i < A.length;i++) A[i]= 7*i;
    display(A);
    System.out.println(A[0]);
    }

    static void display( final int[] V) {
    V[0]=17; // WHY NO ERROR here <========================== ?
    for (int i=0; i < V.length;i++)
    System.out.println(i+" "+V[i]);
    }
    }

  2. #2
    Member John Joe's Avatar
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    Default Re: How to protect a parameter beeing modified

    What error you expect here ?
    Whatever you are, be a good one

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    Default Re: How to protect a parameter beeing modified

    Quote Originally Posted by John Joe View Post
    What error you expect here ?
    I thought that declaring the parameter V as final would make any assignments to any element of the array V illegal.
    If this does not work how can I protect a parameter of a method from being modified?
    In C++ I would declare this parameter as
    const Array& V
    which would make any assignments to any element of V an error at compile time.
    Helmut

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    Default Re: How to protect a parameter beeing modified

    Have a looked on this : https://stackoverflow.com/questions/...utable-in-java
    final has no effect on that
    Whatever you are, be a good one

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    Default Re: How to protect a parameter beeing modified

    Quote Originally Posted by John Joe View Post
    Have a looked on this : https://stackoverflow.com/questions/...utable-in-java
    final has no effect on that
    Many thanks for explaining this.

    FLAMES ON
    But let me say that this is fundamental flaw of Java.
    The same is with the lack of "constant" or "final" methods.
    /FLAMES OFF

  6. #6
    Member John Joe's Avatar
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    Default Re: How to protect a parameter beeing modified

    So glad you found the solution
    Whatever you are, be a good one

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