Java

Default Value of Data Types in Java :

Data Type	Default Value (for fields)
byte	0
short	0
int	0
long	0L
float	0.0f
double	0.0d
char	‘u0000’
String (or any object)	null
boolean	false

Live Example : Default value of Data Type

Sample Program that will illustrate Default Value Stored in Each Primitive Data Type Variable

public class DefaultValue {

  static boolean bool;

  static byte by;

  static char ch;

  static double d;

  static float f;

  static int i;

  static long l;

  static short sh;

  static String str;

  public static void main(String[] args) {

    System.out.println("Bool :" + bool);

    System.out.println("Byte :" + by);

    System.out.println("Character:" + ch);

    System.out.println("Double :" + d);

    System.out.println("Float :" + f);

    System.out.println("Integer :" + i);

    System.out.println("Long :" + l);

    System.out.println("Short :" + sh);

    System.out.println("String :" + str);

  }

}

Output :

[468×60]

Bool     :false

Byte     :0

Character:

Double   :0.0

Float    :0.0

Integer  :0

Long     :0

Short    :0

String   :null

Output of Java Program

Question 1

class Base { 

    public void Print() { 

        System.out.println("Base"); 

    }          

} 

  

class Derived extends Base {     

    public void Print() { 

        System.out.println("Derived"); 

    } 

} 

  

class Main{ 

    public static void DoPrint( Base o ) { 

        o.Print();    

    } 

    public static void main(String[] args) { 

        Base x = new Base(); 

        Base y = new Derived(); 

        Derived z = new Derived(); 

        DoPrint(x); 

        DoPrint(y); 

        DoPrint(z); 

    } 

}

Output:

Base

Derived

Derived

--------------------------------------------------------------------------

Question 2




class Test1 {   

    Test1(int x) {

        System.out.println("Constructor called " + x);

    }

}

   

// This class contains an instance of Test1 

class Test2 {    

    Test1 t1 = new Test1(10);   

   

    Test2(int i) { t1 = new Test1(i); } 

   

    public static void main(String[] args) {    

         Test2 t2 = new Test2(5);

    }

}




Output:

The output of the program is Constructor called 10 Constructor called 5.
-----------------------------------------------------------------------------------------




public class Main

{

    public static void gfg(String s)

    {    

        System.out.println("String");

    }

    public static void gfg(Object o)

    {

        System.out.println("Object");

    }

 

    public static void main(String args[])

    {

        gfg(null);

    }

} //end class

Output:

 String

Explanation: In case of method overloading, the most specific method is chosen at compile time.