java calendar

Java Calendar class

The Calendar class is an abstract class that provides a set of methods and calendar fields such as YEAR, MONTH, DAY_OF_MONTH, HOUR, and so on.The java.util.Calendar class is used to get date and time arithmetic.The reason is that there are more than one calendar in the world. GregorianCalendar using in java.Java support Gregorian calendar implementation,

 the java.util.GregorianCalendar class.

 Syntax:

 Calendar ca = new GregorianCalendar();

Calender properties (TO get):

Calendar ca = new GregorianCalendar();

int year                 = ca.get(Calendar.YEAR);

int month              = ca.get(Calendar.MONTH);

int day                   = ca.get(Calendar.DAY_OF_MONTH); // If Jan = 0, not 1

int dayOfWeek      = ca.get(Calendar.DAY_OF_WEEK);

int weekOfMonth  = ca.get(Calendar.WEEK_OF_MONTH);

int weekOfYear     = ca.get(Calendar.WEEK_OF_YEAR);

int hourOfDay   = ca.get(Calendar.HOUR_OF_DAY); // 24 hour clock format

int hour              = ca.get(Calendar.HOUR);        // 12 hour clock format

int minute          = ca.get(Calendar.MINUTE);

int second          = ca.get(Calendar.SECOND);

int millisecond   = ca.get(Calendar.MILLISECOND);

Calender properties (To set):

Calendar ca = new GregorianCalendar();

ca.set(Calendar.DAY_OF_MONTH, 14);

ca.set(Calendar.MONTH, 1); // 1 = FEBRUARY month

ca.set(Calendar.YEAR, 2014);

 Java Calender class program:

import java.util.Calendar;

import java.util.GregorianCalendar;

public class CalendorDemo {

                public static void main(String[] args) {

                                Calendar  ca = new GregorianCalendar();

                                System.out.println(ca.get(Calendar.DATE));

                                System.out.println(ca.get(Calendar.SATURDAY));

                                System.out.println(ca.get(Calendar.FRIDAY));

                                System.out.println(ca.get(Calendar.WEDNESDAY));

                                System.out.println(ca.get(Calendar.FEBRUARY));

                                System.out.println(ca.get(Calendar.AM));

                                System.out.println(ca.get(Calendar.PM));

                                System.out.println(ca.get(Calendar.AM_PM));

                                System.out.println(ca.get(Calendar.PM));

                                System.out.println(ca.get(Calendar.HOUR));

                                System.out.println("*********************");

                               

                                ca.set(2014, 05, 20);                 //set calendar properties 

                                System.out.println(ca.get(Calendar.DATE));

                                System.out.println(ca.get(Calendar.MONTH));

                                System.out.println(ca.get(Calendar.HOUR));

                               

                }

}

Interview Questions:

What a sample java program to get default to get year and month and date?

Which calendar java supports?

Write few calendar get and set properties?

Which class we need to import to get default calendar?

StringTokenizer in java sample program with example

     

StringTokenizer in java

                      

                                     In java the StringTokenizer class is used to break a string into a number of tokens . It is the simple way to break the string.It presents in java.lang.Object package.

Example:

                Welcome to java, world 

Java program:

import java.util.StringTokenizer;

public class StringToken {

            public static void main(String[] args) {

                        String strname = new String(" Java is a high-level programming language originally developed by sun microsystem.");  

                        StringTokenizer st1 = new StringTokenizer(strname," ") ;      //by using space” “ we are splitting string

                        while (st1.hasMoreTokens()) {

            System.out.println(st1.nextElement());                                 

                        }

            }

}

output:

Java

is

a

high-level

programming

language

originally

developed

 by

 sun

 microsystem. 

Interview questions:

What is String Tokenizer?

Why we are using String Tokenizer?

Write a sample program on String Tokenizer in java?

stringbuffer java program with examples

StringBuffer Java Program

public class StringBufferExmp{

     public static void main(String []args){

StringBuffer sb1=new StringBuffer("Tech "); 

sb1.append("World");                  //concatenating string

System.out.println(sb1);             //printing string  Tech World

sb1.insert(1,"Java");              //string is changing now

System.out.println(sb1); //printing string TJavaech World
                                                               

sb1.replace(1,3,"Java"); 

System.out.println(sb1); //printing TJavavaech World                           

sb1.delete(1,3); 

System.out.println(sb1); // printing Tvavaech World 

sb1.reverse(); 

System.out.println(sb1); // printing dlroW hceavavT                                                                               

 System.out.println(sb1.capacity()); // printing  21

     }

}

Output:

Tech World

TJavaech World

TJavavaech World 

Tvavaech World
dlroW hceavavT   

21

java program to swap two numbers

How to swap two numbers without using temporary variable:

public class SwappingNumbers{

     public static void main(String []args){

        int a=10,b=20;

        a=a*b;

        b=a/b;

        a=a/b;

                System.out.println("a = "+a);

                System.out.println("b = "+b);

     }

}

Output:

                        a = 20

                        b = 10

string reverse in java without using string functions

String reverse 

public class StrReverse{

     public static void main(String []args){

String str="Java world";

String revstr="";

int length = str.length();

for(int i=length -1;i>=0;i--){

revstr = revstr + str.charAt(i);

}

System.out.println(revstr);

     }

}

Output:

dlrow avaJ

java inheritance sample program

Java Inheritance Program:

Super class

package com.java.Inheritanceclass;                               //package

public class SuperClass {

           

            int num;

            public SuperClass( int num) {                       //Constructor 

                        super();

                        System.out.println("Super Class");

                        this.num=num;

                        System.out.println(num);

             

            }

            public int getNum() {

                        return num;

            }           

}

Sub class

package com.java.Inheritanceclass;

public class SubClass extends SuperClass {                //extending super class

          

            int Subnum;

           

            public SubClass(int num1, int num2) {

                        super(num1);

                        System.out.println("Sub Class");

                        Subnum = num2;

            }

            public int getSubnum()

            {

                        return Subnum;

            }

}

Main method class

package com.java.Inheritanceclass;

public class Main {

 public static void main(String[] args) {

      SubClass sub = new SubClass(12, 10);                     //creating object

      System.out.println(sub.getSubnum());

     

            }

}