Methods and variables


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Thread: Methods and variables

  1. #1
    Join Date
    Aug 2002
    Posts
    3

    Methods and variables

    Being new at java, I have this question. Methods and variables that are associated with a class rather than with instances are declared private. Is this correct?

  2. #2
    Join Date
    Aug 2002
    Posts
    5
    I may be wrong but I believe that methods and variables that are associated with a class are called static, rather than private. You can declare either static or non-static members private if you need to restrict them from being accessed by anything outside of the class they were declared in.

  3. #3
    Join Date
    Aug 2002
    Posts
    94
    First about static part:

    Any variable declared static will have same value throughout all the instances of that class e.g

    public class family{
    String first_name;
    static String family_name="Mathur";
    int age;
    String gender;
    }

    if we create instances of this class say :
    family father-new family();
    family son-new family();

    then father.first_name & son.first_name can have different values but both the instances of family class will have common value for variable "family_name" or in other words if you change the value of family_name to say "Wilkes" then it will change for all its instances.

    Second part is :
    Protected, private & public are the acess control levels (deault is public) and have following implications:

    Private: the method/variable cannot be seen or used by any other class unless called through an internal function of same class.

    Protected: the method can only be called from subclasses or classes within same package.

    Public: allows any class to acess and manipulate value of this variable.

    Bye

  4. #4
    Join Date
    Sep 2002
    Posts
    3
    I think your description of static is good, but missing one important point.

    If you declare a member variable or method static, you can access those items without having to create an object. So, if you make a really cool class for printing your name 10 times to the screen, such as:

    Code:
    public class ReallyCoolNameClass
    {
        static void printName(String name)   
        {
            for(int i = 0; i <=10; i++)
                System.out.println(name);
        }
    }
    You can use this in your code like this:

    Code:
    ReallyCoolNameClass.printName("Doug");
    Instead of having to do this:

    Code:
    ReallyCoolNameClass name = new ReallyCoolNameClass();
    name.printName("Doug");
    This is probably a dumb and bad example, but hopefully it gets the point across.

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