significance of static variables and methods

[imran_khan]

Hi,
can anyone tell me the significance of using static variables and methodsin an elaborative way?

[yiweiang]

Hi,

In simple terms, Static methods and Variables can be called without being instantiated. In fact, they cannot be instantiated.

So you have a class Shirt.

public class Shirt
{
public static int quantity=1000;


//rest of the code

}

then you have two subclasses of Class Shirt

public class Jacket extends Shirt
{

psvm(String Args[])
{
System.out.println(Shirt.quantity); //prints out 1000
Shirt.quantity=Shirt.quantity-100; //Now quantity is 900
}

}

public class TShirt extends Shirt
{

psvm(String Args[])
{
System.out.println(Shirt.quantity); //prints 900 because they are referring to the same thing

}

}

[cruxblack]

The keyword static also means that the variable declared as static are used as a class variable, in terms of that there exist only one copy of this variable in the memory, no matter how much instance that class have

If u don't use the static keyword, when each instance are constructed they would get each a acopy of the variable, but if it's declared static, then the variable refer to the class variable in which if u modify the variable in an instance, then the rest of the other instances also get the effect

Since it's static, and just like we have discussed before are considered as a class variable or class method, we don't need to instantiate an object to use it, instead we just use the classname.variable or classname.method() to call it

[imran_khan]

Thanks for ur reply.static variables are clarified but pls clarify more on static methods.

[yiweiang]

Static methods are basically methods that need not be initiated to be called upon. Assuming that the class is in the same package, or if you have imported the class, just doing this will allow you to use the method:

theClassOfTheStaticMethod.methodName();

Yi Wei