java program for super keyword

Write a java program to given the example for “super” keyword.

super() is used to invoke super class constructors and super keyword is refer super class members.

in this program i did show the difference with and without super keyword.

by using super keyword we can access parent class properties.

public class SuperTest {

       int number=10;

       SuperTest(){

        System.out.println("parent class constructor ");

       }     

}

class Test extends SuperTest{    

       int number=20;      

       Test(){

              super();

              System.out.println("using super keyword :" +super.number);

              System.out.println("with out using super keyword :" +number);

       }     

       public static void main(String[] args) {

              Test obj=new Test();      

       }

}

OUTPUT:

/*

parent class constructor

using super keyword :10

with out using super keyword :20

*/

java program for static variables, methods, and blocks.

Write a java program to demonstrate static variables, methods, and blocks.

We can access static variables, blocks, and methods without creating object as shown in the below program.

JVM first check for the main method and after checking the main method it will execute static block after that execute remaining code.

public class StaticTest {

       static int id=1214; 

       static{

              String name="narendar";

              System.out.println("static block "+name);

       }

       static void display(){

              String group="CSIT";

              System.out.println("static method "+group);

       }     

       public static void main(String[] args) {

              System.out.println("static variable "+id);

              display();          

       }

}

Output:

/*

static block narendar

static variable 1214

static method CSIT

*/

java program for exception handling mechanism

 Write a java program that describes the exception handling mechanism.

To handle exception we use try, catch, finally block. In try block we write risky code. If any exception will occur in try block, that exception handle in catch block. Try block will execute if exception is occur or not.

In this program we will get ArithmeticException in try block, we are handling that exception in catch block.

We will get output catch-finally block instead of try block.

public class ExceptionTest {

       public static void main(String[] args)

       {

              try

              {

                     int a=10;

                     int b=0;

                     int c=a/b;

                     System.out.println(c);

              }

              catch(ArithmeticException ae)

              {

                     System.out.println(10);                 

              }

              finally

              {

                     System.out.println("finally");

              }            

       }

}

OUTPUT:

/*

10

Finally

*/

Example for command line arguments

Write a java program give example for command line arguments.

public class CammandTest {

       public static void main(String[] args) {

              System.out.println(args[0]);

              System.out.println(args[1]);

              System.out.println(args[0]+args[1]);

       }

}

OUTPUT:

/* D:\Java>java CammandTest javathub blogspot

javathub

blogspot

javathubblogspot*/

Default values of all primitive data types

Write a java program to display default value of all primitive data types of java.

Default Values of all primitive data types:

Data Type	Default Value
byte	0
short	0
int	0
long	0L
float	0.0f
double	0.0d
char	‘u0000’
String	null
boolean	false

public class DefaultValue {

       byte b;

       short s;

       int i;

       long l;

       float f;

       double d;

       char ch;

       String str;

       boolean flag;      

       public static void main(String[] args) {             

              DefaultValue dv=new DefaultValue();

              System.out.println("byte value : " +dv.b);

              System.out.println("short value : " +dv.s);

              System.out.println("int value : " +dv.i);

              System.out.println("long value : " +dv.l);

              System.out.println("float value : " +dv.f);

              System.out.println("double value : " +dv.d);

              System.out.println("char value : " +dv.ch);

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

              System.out.println("boolean value : " +dv.flag);

       }

}

OUTPUT:

byte value : 0

short value : 0

int value : 0

long value : 0

float value : 0.0

double value : 0.0

char value :

String value : null

boolean value : false

we get blank space for char data type