import java.util.Date;

// Static imports are used to import static variables and methods as below

import static java.lang.Math.PI; // Static variable

import static java.lang.Math.abs; // Static method

/**

* This class intends to demonstrate the usage of static keyword in Java

*/

public class StaticDemonstration {

private final String name;

private static final String time = new Date().toString();

/* Static block gets executed when the class is loaded by the JVM.

This happens at the beginning of the execution.

*/

static {

System.out.println("Class being loaded");

}

public StaticDemonstration(String name) {

this.name = name;

}

/* Main method is a static method meaning that it can be

called without requiring an instance of the containing class.

*/

public static void main(String[] args) {

System.out.println("Value of PI: " + PI);

System.out.println("Value of abs(-1): " + abs(-1));

System.out.println("Time is: " + time); //static main method can use static variables in the class without an instance

greet(); // static main method can call other static methods in the class without an instance

StaticDemonstration staticDemonstration = new StaticDemonstration("Java Developer");

staticDemonstration.greetUser(); // To call a non-static method, an instance is needed

System.out.println("Name is: " + staticDemonstration.name); // To access non-static members, an instance is needed

// Static nested class can be initialized without requiring an instance of the enclosing class

StaticNestedClass staticNestedClass = new StaticNestedClass();

// Non static inner class requires an instance of enclosing class to be instantiated

NonStaticInnerClass nonStaticInnerClass = staticDemonstration.new NonStaticInnerClass();

}

private static void greet() {

System.out.println("Hello user. Have a good day.");

}

private void greetUser() {

System.out.println("Hello " + name + ". Have a good day.");

}

private static class StaticNestedClass {

private StaticNestedClass() {

System.out.println("StaticNestedClass constructor");

}

}

private class NonStaticInnerClass {

private NonStaticInnerClass() {

System.out.println("NonStaticInnerClass constructor");

}

}

}