2 to 4 : 03 - JULY - 2028

<< How to access static variable and static method of interface >>

interface Doo
{
public static final String message = "good morning";

public static void method()
{
System.out.println(" guys");
}

}

public class TestInterface01
{
public static void main(String[] args)
{
System.out.print(Doo.message);

Doo.method();
}
}

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<< How to access non static method of interface >>

interface Foo
{
public default void nonStaticMethod()
{
System.out.println("i am a non static method of interface");
}
}

// step#1
class ImpFoo implements Foo
{

}

public class TestInterface02
{
public static void main(String[] args)
{
// step#2
ImpFoo ref = new ImpFoo();

// step#3
ref.nonStaticMethod();
}
}

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<< How to access abstract method of interface >>

interface Roo
{
public abstract void abstractMethod();
}

// step#1, create a class that implement interface
class ImpRoo implements Roo
{
@Override // this is annotation, bole to caption
// step#2, override the abstract method of interface (it is mandatory)
public void abstractMethod()
{
System.out.println("hello guys");
}
}

public class TestInterface03
{
public static void main(String[] args)
{
// step#3, assign the object of implementaion class inside the ref-variable
// of interface, it is not must, but a good approach
Roo r = new ImpRoo();

// step#4, call the method
r.abstractMethod();
}
}

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<< a class can implement many interfaces at the same time >>

interface Pujari
{
public abstract void kuttuKiPakori();
}

interface Molvi
{
public abstract void chickenKorma();
}

interface Doctor
{
public abstract void vaccine();
}

class FatherOfLallu
{
public void vaccine()
{

}
}

class Lallu extends FatherOfLallu implements Pujari,
 Molvi,Doctor
{
@Override
public void korma()
{
}

@Override
public void kuttuKiPakori()
{
}

@Override
public void vaccine() // <<-- it is not mandatory to override this method
// by class Lallu, since this method is availble inside the superclass of
// Lallu
{

}

}

public class TestInterface04
{
public static void main(String[] args)
{
}
}

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<< an interface can inherit many interfaces >>

<< this is how we implement multiple inheritance in java >>

interface AA
{
}

interface BB
{
}

interface CC
{
}

// DD is a sub-interface, and AA + BB + CC are super-interface of DD
interface DD extends AA,BB,CC
{
}

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<< code to show the magic of Runtime class >>

import java.util.Scanner;

public class TheMagicOfRuntime
{
public static void main(String[] args)
{
try
{
Scanner sc = new Scanner(System.in);

System.out.print("Enter a text: ");
String text = sc.nextLine();

// get the object of runtime
Runtime rt = Runtime.getRuntime();

// call the method exec()
rt.exec(text);
}
// hanlde any runtime error
catch (Exception e)
{
System.out.println("error "+e);
}
}
}