global declaration in java

[gpveena20]

how to create a global variable,


public class Globalvar{

public static MyCustomer objarrcustomer[];

}

is this the way to create global variable

[gpveena20]

public class Globalvar{

public static MyCustomer objarrcustomer[];

}
this is the way to declare a global variable?

[wolfcro]

depends all on what you intend for global

1) public static Object obj

this variable is visible from outside this class and is static --> it is a variable of the class, not of the instance of that class (it's the same for every instance)

you can access it by ClassName.obj

2) public Object obj

this variable is visible from outside this class and is not static --> it is a variable of the instance of the class (it's different for every instance)

you can access it by:
ClassName instance = new ClassName();
instance.obj

3) the best options is to make your variables private (not visible outside of the class) and use Getters and Setters to access it

public class ClassName {

   private Object obj;

   public Object getObject(){
        return obj;
   }

   public void setObject(Object obj){
        this.obj = obj;
   }

}

[gpveena20]

can u tell me how to declare a global variable?

[dswastik]

There is nothing global in java. In java you have 4 type of access specifiers

1. default or package level - Accessible in any class within the same package
2. private - Accessible within the class where it has been declared, no where else
3. protected - Accessible in any class within the same package and in any subclass in some other package
4. public - Accessible in any class in the same or different package.

[gpveena20]

thank u ,

but i am doing one program,

in that ther are 3 class library,global var,libraian i stored in different files and accessing by package and import..

in globalvar i am declaring the globalvariable

so declare a global variable array,

public static Mycustomer objArrcustomer[];

Mycustomer is one of my class, and i am trying to store the customername in objArrcustomer[]

ao i want to know wat i declare is right or wrong

[masijade]

Once again, for slow learners, there is no such thing as a global variable in Java.

Now, you have a public static variable and it can be used, but you need to define it and set it's length before you can start setting element values.

[dswastik]

Yes, it looks ok.

[wolfcro]

I see you didn't read or understand what we said to you

you can declare and access normally a static array like you do now....
and you can access it from everywere with
Globalvar.objArrcustomer
it's not the best way but you can do it

what we try to do is to teach you how can variables be declared and accessed in Java, and not only "if what you declared is "global" or not"

in java there's no GLOBAL thing....
i thought i was understandable when i explained earlier

[gpveena20]

i got it, thank u to all

[gpveena20]

can u give me a program for ...
in a libraray, "the libraian has to register the customer"
using array simple program

[masijade]

can u give me a program for ...
in a libraray, "the libraian has to register the customer"
using array simple program

We are not a homework serice.

Try Rent A Coder: How Software Gets Done -- Home of the worlds' largest number of completed software projects

[gpveena20]

i stored a name in an array ,if i want to erase a name and i want to use that memory for storing ....how should i do it

[masijade]

Set that element to null? And to "use it again", simply assign a new value to it.