In the previous article, we have discussed the do-while loop which is a continuation post of core Java tutorial post, we are going to learn about the static keyword in java. Because In Java programming language static keyword is used regularly.
The Static keyword in Java used for memory management. we can use the static keyword with class, variable, methods and block. If a class have static members then that belongs to the classes instead of specific instances. that means if you make a member static then we can invoke those members without creating the objects.
Before going deep let’s take a simple example for better understand how the static keyword works.
class SimpleStaticEx
{
// This is a static method
static void myDemoMethod()
{
System.out.println("Method Executed");
}
public static void main(String[] args)
{
/* We are calling a static method without creating an object */
myDemoMethod();
}
}We have seen in the above example, the myDemoMethod is a static method and we are calling that method without creating an object. That means when we are creating a static member, then that is created at the class level. If we are removing the static keyword then for access that member we have to create an instance of that class otherwise we can’t access that.
Static Variables
When you have declared a variable with the keyword static, then a single copy of that variable is created and shared among all objects or instances of the class. Mostly when we are declaring some global variables we define those variables with the static keyword. so that all instances of those classes can share the same static variable.
Note:
- We can create a static variable at a class level only.
- The execution order of Static variable and the static block is the same the order as they are present in the program.
Let’s take an example to understand how the static variable and static block are executed.
Program
Static Method
When we define a method with the static keyword that method is called a static method. The Common static method which we regularly use when we are writing in any java program is the main() method. As we discussed above we can access any static member before creating any objects of that class and without reference to any object that’s, why main() is executed without creating an object of that class.
The static method has several restrictions like:
- They can directly call other static methods and static members.
- Can not refer to this or super variable or methods.
When do you need to use Static variables and methods?
You should use the static variables to those properties which are common for all. For example in an organization, all employees share the same organization name. Similarly, for change the static variables value we need static methods.
Static Blocks
Static blocks are mainly used to initialize the static variables. This static block gets executed only once at the time of the class is loaded into the memory.
For Better understanding refer to the below program:
Static Nested Classes
We can not declare the top-level classes with static modifiers, but we can declare the inner classes with static modifiers. Such types of classes called Nested static classes.
Ref: article
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