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Thread: Instance data member vs Local variables (primitive/object reference)

  1. #1
    Java kindergarten chronoz13's Avatar
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    Mar 2009
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    Default Instance data member vs Local variables (primitive/object reference)

    just a simple question: why does a local variable should be initialized before a program's running stage? considering that this variable will be used somewhere local, while a data member can be used even if it is not initialized in a constructor or an instance method.
    does the compiler always assign an offset values in data members when they are not initialized explicitly?

  2. #2
    Join Date
    Jun 2011
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    Default Re: Instance data member vs Local variables (primitive/object reference)

    Here is an explanation for both of your questions: oop - Uninitialized variables and members in Java - Stack Overflow
    The compiler forces you to initialize local variables partly because it can not figure out the full logic of your program flow.

    Edit: My compiler optimizes away the first increment but not the second. Whether this should be an error or a warning is
    debatable but that is the way it is in java.
    public void foo() {
         int x;
         final int y = 0;
         if(y == 0)
    Last edited by dabdi; September 23rd, 2011 at 01:12 AM.

  3. The Following User Says Thank You to dabdi For This Useful Post:

    chronoz13 (September 23rd, 2011)

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