Java Tutorials

Java Program to convert Decimal values to Hexadecimal values

Objectives :

How to convert Decimal to Hexadecimal in Java?

Java Program to convert Decimal values to Hexadecimal values :

[sourcecode lang=”java”]

import java.util.Scanner;

public class DecimalToHexadecimal {

public static void main(String[] args) {

Scanner input = new Scanner(System.in);

System.out.print("Enter decimal number you like: ");
int deci = input.nextInt();

System.out.println("The hexadecimal number for decimal "
+ deci + " is " + convert(deci));
}

public static String convert(int decimal) {
String hex = "";

while (decimal != 0) {
int hexValue = decimal % 16;
hex = toHexadecimal(hexValue) + hex;
decimal = decimal / 16;
}

return hex;
}

public static char toHexadecimal(int hexValue) {
if (hexValue <= 9 && hexValue >= 0) {
return (char) (hexValue + ‘0’);
} else {
return (char) (hexValue – 10 + ‘A’);
}
}
}

[/sourcecode]

Output :
Enter decimal number you like: 1234
The hexadecimal number for decimal 1234 is 4D2

Java Program to Convert Decimal Number to Roman Number

Objectives :

Convert Decimal number to Roman number
Convert Decimal numeral to Roman numeral
How to convert a decimal number to roman number
Write a program that converts a decimal number to Roman number.
Write a program that converts a decimal number to Roman number. Decimal Number is accepted using Scanner class at the time of execution.
Write a program that converts a decimal number to Roman number. Decimal Number is accepted as command line input at the time of execution.

Program :

Java program that converts a decimal number to Roman number. Decimal Number is accepted using Scanner class at the time of execution.

[sourcecode lang=”java”]

import java.util.Scanner;

public class DecimalToRoman {

private static String toRoman(int num) {
String[] romanCharacters = { "M", "CM", "D", "C", "XC", "L", "X", "IX", "V", "I" };
int[] romanValues = { 1000, 900, 500, 100, 90, 50, 10, 9, 5, 1 };
String result = "";

for (int i = 0; i < romanValues.length; i++) {
int numberInPlace = num / romanValues[i];
if (numberInPlace == 0) continue;
result += numberInPlace == 4 && i > 0? romanCharacters[i] + romanCharacters[i – 1]:
new String(new char[numberInPlace]).replace("\0",romanCharacters[i]);
num = num % romanValues[i];
}
return result;
}

public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("Enter a number : ");
int decimal = scanner.nextInt();
System.out.println(toRoman(decimal));
}

}

[/sourcecode]

Output :

Enter a number : 1234

MCCXXXIV

Java program that converts a decimal number to Roman number. Decimal Number is accepted as command line input at the time of execution.

[sourcecode lang=”java”]

public class DecimalToRoman {

private static String toRoman(int num) {
String[] romanCharacters = { "M", "CM", "D", "C", "XC", "L", "X", "IX", "V", "I" };
int[] romanValues = { 1000, 900, 500, 100, 90, 50, 10, 9, 5, 1 };
String result = "";

for (int i = 0; i < romanValues.length; i++) {
int numberInPlace = num / romanValues[i];
if (numberInPlace == 0) continue;
result += numberInPlace == 4 && i > 0? romanCharacters[i] + romanCharacters[i – 1]:
new String(new char[numberInPlace]).replace("\0",romanCharacters[i]);
num = num % romanValues[i];
}
return result;
}

public static void main(String[] args) {
if(args.length<1 || args.length>1){
System.out.println("Wrong input");
}else{
String number = args[0];
int decimal = Integer.parseInt(number);
System.out.println(toRoman(decimal));
}
}

}

[/sourcecode]

March 28, 2016 by Aatul Palandurkar Java Source Code Java Tutorials NetBeans IDE Source Code 1

Passing data between activities in Android

Objective :

Passing data between activities in Android
Passing multiple data between activities in Android
Passing array between activities in Android
Passing ArrayList between activities in Android
Passing ArrayList to another activity in Android
Sending data via Intent in Android
Sending multiple data via Intent in Android
Sending array between activities in Android
Sending ArrayList between activities in Android
Sending ArrayList to another activity in Android
Sending data via Intent and Bundle in Android
Sending multiple data via Intent and Bundle in Android
Passing array between activities in Android using Intent and Bundle
How to pass array to another activity in Android?
How to pass array between activities in Android?
How to pass data to another activity in Android?
How to pass data to activity in Android?
How to pass data to between activities in Android?
How to pass ArrayList to another activity in Android?
How to pass ArrayList between activities in Android?

Code for passing data between activities in Android :

ActivityOne.java

[sourcecode lang=”java”]

String value = "Hello!";
Intent in = new Intent(this,ActivityTwo.class);
in.putExtra("Key", value);
startActivity(in);

[/sourcecode]

ActivityTwo.java

[sourcecode lang=”java”]

Bundle bundle = getIntent().getExtras();
String valueReceived = bundle .getString("Key");

[/sourcecode]

Code for passing multiple data or values between activities in Android :

Method 1 : Using Intent to pass data and Bundle to extract data between activities in Android

ActivityOne.java

[sourcecode lang=”java”]

String value1 = "Hello!";
String value2 = "Hi!";
Intent in = new Intent(this,ActivityTwo.class);
in.putExtra("Key1", value1);
in.putExtra("Key2", value2);
startActivity(in);
[/sourcecode]

ActivityTwo.java

[sourcecode lang=”java”]
Bundle bundle = getIntent().getExtras();
String valueReceived1 = bundle .getString("Key1");
String valueReceived2 = bundle .getString("Key2");
[/sourcecode]

Method 2 : Using Bundle to pass and to extract data between activities in Android

ActivityOne.java

[sourcecode lang=”java”]

String value1 = "Hello!";
String value2 = "Hi!";
Intent in = new Intent(this,ActivityTwo.class);
Bundle bundle = new Bundle();
bundle.putString("Key1", value1);
bundle.putString("Key2", value2);
in.putExtras(bundle);
startActivity(in);
[/sourcecode]

ActivityTwo.java

[sourcecode lang=”java”]
Bundle bundle = getIntent().getExtras();
String valueReceived1 = bundle .getString("Key1");
String valueReceived2 = bundle .getString("Key2");
[/sourcecode]

Code for passing array between activities in Android :

ActivityOne.java

[sourcecode lang=”java”]
String[] array = new String[]{"Item1", "Item2", "item3", "Item4", "item5"};
Intent in = new Intent(this,ActivityTwo.class);
Bundle bundle = new Bundle();
bundle.putStringArray("MyArray", array);
in.putExtras(bundle);
startActivity(in);
[/sourcecode]

ActivityTwo.java

[sourcecode lang=”java”]
Bundle bundle = getIntent().getExtras();
String arrayReceived[] = bundle.getStringArray("MyArray");
[/sourcecode]

Code for passing ArrayList between activities in Android :

ActivityOne.java

[sourcecode lang=”java”]
ArrayList<String> array = new ArrayList<String>();
array.add("Hello");
array.add("Hi");
array.add("Bye");
Intent intent = new Intent(this, ActivityTwo.class);
intent.putExtra("array_list", array);
startActivity(intent);
[/sourcecode]

ActivityTwo.java

[sourcecode lang=”java”]
Bundle bundle = getIntent().getExtras();
ArrayList<String> array = (ArrayList<String>) bundle.getStringArrayList("array_list");
[/sourcecode]

Have fun with Intent.

March 19, 2016 by Aatul Palandurkar Android Source Codes Android Tutorials Java Source Code Java Tutorials 1

Java Program to Convert Binary to Decimal

Objectives :

Binary to Decimal Conversion
Converting Binary to Decimal
Write a program to convert binary to decimal
Write a program to convert binary number to decimal format
Write a program to convert binary to decimal using Scanner class
Write a program to convert binary to decimal, take input using Scanner class

Java Program :

[sourcecode lang=”java”]

import java.util.Scanner;

public class BinaryToDecimal {

public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("Enter binary number: ");
String binary = scanner.nextLine();
int decimal = binaryToDecimal(binary);
System.out.println("Decimal equivalent of "+ binary +" is "+ decimal);
}

private static int binaryToDecimal(String binary) {
final int base = 2;
int decimal = 0;
for (int i = 0; i < binary.length(); i++) {
if (binary.charAt(i) == ‘0’) {
decimal += 0 * Math.pow(base, binary.length() – i – 1);
} else if (binary.charAt(i) == ‘1’) {
decimal += 1 * Math.pow(base, binary.length() – i – 1);
} else {
System.out.println("Invalid Binary Number");
System.out.println("Binary Number Contains only 0’s or 1’s");
System.exit(0);
}
}
return decimal;
}
}

[/sourcecode]

Output :
Enter binary number: 1110
Decimal equivalent of 1110 is 14

March 16, 2016 by Aatul Palandurkar Java Source Code Java Tutorials 1

Java Program to convert Decimal to Binary

Objectives :

Decimal to Binary Conversion
Converting Decimal to Binary
Converting Decimal Number to Binary format
Write a program to convert decimal to binary
Write a program to convert decimal number to binary format
Write a program to convert positive decimal number to binary format
Write a program to convert decimal to binary using Scanner class
Write a program to convert decimal to binary, take input using Scanner class

Java Program to convert Decimal to Binary :

[sourcecode lang=”java”]
public class DecimalToBinary {

public void toBinary(int number){
int binary[] = new int[25];
int n = 0;
// Convert Decimal to Binary
while(number > 0){
binary[n++] = number%2;
number = number/2;
}
// Print Binary number
for(int i = n-1;i >= 0;i–){
System.out.print(binary[i]);
}
}

public static void main(String[] args){
DecimalToBinary obj = new DecimalToBinary();
obj.toBinary(14);
}
}
[/sourcecode]

Output :

1110

Java Program to convert Decimal to Binary using Scanner class :

[sourcecode lang=”java”]

import java.util.Scanner;

public class DecimalToBinary {

public void toBinary(int number){
int binary[] = new int[14];
int n = 0;

// Convert Decimal to Binary
while(number > 0){
binary[n++] = number%2;
number = number/2;
}

// Print Binary Number
for(int i = n-1;i >= 0;i–){
System.out.print(binary[i]);
}
}

public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("Enter a number: ");
int num= scanner.nextInt();
DecimalToBinary obj = new DecimalToBinary();
obj.toBinary(num);

}
}

[/sourcecode]

Output :

Enter a number: 14

1110

March 15, 2016 by Aatul Palandurkar Java Tutorials 1

Java Program to find prime number upto N number

Objectives :

Write a Java program to find prime number upto N number
Write a Java program to print prime number upto N number
Write a Java program to find prime number upto N number using Command Line Arguments
Write a Java Program to find prime number upto N number via Command Line Arguments
Write a Java program to find prime number upto N number using Scanner class

Java Program / Code :

Method 1 : Java Program to find Prime Number upto N number using Scanner class

[sourcecode lang=”Java”]

import java.util.Scanner;
class PrimeNumber
{
public static void main(String[] args)
{
int n,p;
Scanner s=new Scanner(System.in);
System.out.println(“Enter number : ”);
n=s.nextInt();
for(int i=2;i<n;i++)
{
p=0;
for(int j=2;j<i;j++)
{
if(i%j==0)
p=1;
}
if(p==0){
System.out.println(i);
}
}
}
}
[/sourcecode]

Method 2 : Java Program to find Prime Number upto N number using Scanner class and writing function to find prime number

Method isPrime() for checking if a number is prime or not

[sourcecode lang=”java”]
public class PrimeNumber{
public boolean isPrime(int num) {
if ( num < 2 ){
return false;
}
for (int i = 2; i <= Math.sqrt(num); i++) {
if ( num % i == 0 ) {
return false;
}
}
return true;
}
}

// Mock Test Class to test above code
import java.util.Scanner;

public class Demo
{
public static void main(String[] args)
{
Scanner scanner = new Scanner(System.in);

System.out.println("Please enter a number: ");
int num = scanner.nextInt();

if ( num < 2 ) {
System.out.println("\n There are no Prime Numbers available");
System.exit(0);
}
System.out.println("\n Prime Numbers from 1 to "+ num);
PrimeNumber primeNum = new PrimeNumber();

for (int i = 3; i <= num; i++) {
if ( primeNum.isPrime(i) ) {
System.out.print(", " + i);
}
}
}
}
[/sourcecode]

Method 3 : Java Program to find Prime Number upto N number using Command line input

[sourcecode lang=”Java”]

class PrimeNumber
{
public static void main(String[] args)
{
int n,p;
n=Integer.parseint(args[0]);
for(int i=2;i<n;i++)
{
p=0;
for(int j=2;j<i;j++)
{
if(i%j==0)
p=1;
}
if(p==0){
System.out.println(i);
}
}
}
}
[/sourcecode]

Steps to run above program via command line :

Compilation : C:\JavaPrograms>javac PrimeNumber.java
Interpretation : C:\JavaPrograms>java PrimeNumber 20

Output :

2

3

5

7

11

13

17

19

March 13, 2016 by Aatul Palandurkar Java Tutorials 1

Program to find Sum of Digits in Java

Objectives :

Write a program to compute sum of digits of a given number.
Write a program to find sum of digits of a given number.
Write a program to calculate sum of digits of a given number.
Write a program to compute sum of digits of a given integer number.
Write a program to compute sum of digits of a number entered via Command Line.
Write a program to compute sum of digits of a given number. Take input from Command Line.
Write a program to compute sum of digits of a given number. Take input using Scanner class.

Following is the Java Program to compute Sum of Digits of a given integer number;

Method 1 : Java Program to find Sum of Digits when number is entered from command line

[sourcecode lang=”java”]

class SumOfDigits
{
public static void main(String args[])
{
int n;
int a=0;
int sum=0;

//taking integer number from command line and parsing the same
n=Integer.parseInt(args[0]);

while(n!=0)
{
a=n%10;
n=n/10;
sum=sum+a;
}
System.out.println("Sum of digits: " + sum);
}
}

[/sourcecode]

Steps to run above program via command line :

Compilation : C:\JavaPrograms>javac SumOfDigits.java
Interpretation : C:\JavaPrograms>java SumOfDigits 12345

Output : Sum of digits: 15

Method 2 : Java Program to find Sum of Digits if input is taken using Scanner class

[sourcecode lang=”java”]

import java.util.Scanner;

public class SumOfDigits {
public static void main(String args[]) {
Scanner in = new Scanner(System.in);
int n;
int a=0;
System.out.print("Enter a positive number: ");
n = in.nextInt();

if (n <= 0)
System.out.println("You have entered a negative number.");
else {
int sum = 0;

while (n != 0) {

a=n%10;
n=n/10;
sum=sum+a;
}
System.out.println("Sum of digits: " + sum);
}
}
}

[/sourcecode]

Steps to run above program via command line :

Compilation : C:\JavaPrograms>javac SumOfDigits.java
Interpretation : C:\JavaPrograms>java SumOfDigits 12345

Output :

Trial 1 : With positive number

Enter a positive number: 12345

Sum of digits: 15

Trial 2 : With negative number

Enter a positive number: -12345

You have entered a negative number.

February 23, 2016 by Aatul Palandurkar Java Source Code Java Tutorials 1

Simple Interest Example in Java

Starting a series of some Java programs as many students were asking to share the programs. Here is the first program of the series.

Objectives:

Write a Program that calculates and prints the simple interest using the formula : Simple Interest = PTR/100
How to calculate Simple Interest in Java?
Write a program to calculate Simple Interest in Java.
Write a Java program that calculates and prints the simple interest using the formula : “SimpleInterest = PTR/100” and input values P, T, R should be accepted as command line.
How to use Command Line Arguments in Java?
How to pass values from command line in Java?
How to take input in Java from console?

This particular program can be written in various ways, we will try to write the solution program in different ways here and one can try to understand the difference between them.

Method 1 :

[sourcecode lang=”java”]
import java.util.Scanner;

public class SimpleInterestExample {

public static void main(String[] args) {

int p,t,r, result;

Scanner sc = new Scanner(System.in);

System.out.println("Enter the Value of P : ");
p = sc.nextInt();

System.out.println("Enter the Value of T : ");
t = sc.nextInt();

System.out.println("Enter the Value of R : ");
r = sc.nextInt();

result = (p*t*r)/100;
System.out.println("Interest is : " + result);
}
}
[/sourcecode]

This one is the simplest way to write the program to find simple interest in Java. Here we have simply created the object of Scanner class for taking input. Scanner class was introduced in Java 6. To use Scanner class we will have to import the class from java.util package.

Method 2:

Now we will write a Java program that calculates and prints the simple interest using the Scanner class again but with object oriented programming approach.

[sourcecode lang=”java”]
import java.util.Scanner;

public class SimpleInterestExample
{
double principalAmount = 0;
double interestRate = 0;
double term = 0;
double simpleInterest = 0;

public void calculateSimpleInterest()
{
Scanner input = new Scanner(System.in);

System.out.print("Enter the Principal amount : ");
principalAmount = input.nextDouble();

System.out.print("Enter the Rate As a decimal : ");
interestRate = input.nextDouble();

System.out.print("Enter the amount of time in years : ");
term = input.nextDouble();

simpleInterest = (principalAmount * interestRate * term) / 100;
}

public void displaySimpleInterest()
{
System.out.println("The Simple Interest is : " + simpleInterest);
}
}
[/sourcecode]

Mock Test Program for above code so that we can test the code. keep both the classes in same package and run the Mock Test Program or MockTestProgram.java

[sourcecode lang=”java”]
public class MockTestProgram{

public static void main(String[]args);
{
SimpleInterestExample simpleInt = new SimpleInterestExample();
simpleInt.calculateSimpleInterest();
simpleInt.displaySimpleInterest();
}
}
[/sourcecode]

Method 3:

Now we will write a Java program that calculates and prints the simple interest using the formula : “SimpleInterest = PTR/100” and input values P, T, R should be accepted as command line.

[sourcecode lang=”java”]
import java.util.Scanner;

public class SimpleInterestExample {

public static void main(String[] args) {
double p,t,r, result;

p = Double.parseDouble(args[0]);
t = Double.parseDouble(args[1]);
r = Double.parseDouble(args[2]);

Scanner sc = new Scanner(System.in);

System.out.println("Enter the Value of P : ");
p = sc.nextDouble();

System.out.println("Enter the Value of T : ");
t = sc.nextDouble();

System.out.println("Enter the Value of R : ");
r = sc.nextDouble();

result = (p*t*r)/100;
System.out.println("Interest is : " + result);
}
}
[/sourcecode]

I will be sharing more programs soon as many students were asking for programs which were carried out during Java training and were asked in assignments after Java training. By the time enjoy coding in Java and use NetBeans, it will ease your life.

July 20, 2015 by Aatul Palandurkar Java Source Code Java Tutorials 0

7 differences between HashMap and HashTable

Objectives:

What is HashMap?
What is HashMap in Java?
What is HashTable?
What is HashTable in Java?
What are the differences between HashMap and HashTable?
What are the differences between HashMap and HashTable in Java?

HashMap vs HashTable

1. HashMap is non-synchronized. HashTable is synchronized.

2. HashMap is not thread safe. HashTable is thread safe.

3. HashMap allows one null key and any number of null values while HashTable do not allow null keys and null values in HashTable Object.

4. HashMap object values are iterated using iterator. HashTable is only class other than Vector class which uses enumerator to iterate values of HashTable object.

5. The iterator in HashMap is fail-fast iterator while enumerator for HashTable is not.

6. HashMap is much faster and uses less memory than HashTable.

7. HashMap is subclass of AbstractMap class. HashTable is subclass of Dictionary class which is obsolete in 1.7 and not in use anymore.

June 7, 2015 by Aatul Palandurkar J2EE Tutorials Java Tutorials 0

Book : NetBeans IDE How-to Instant

NetBeans IDE How-to : Atul Palandurkar : Packt Publishing, UK

I was asked to write a book for Java Application Development using NetBeans IDE by PACKT Publishing, UK which is one of the leading technology books publishers in world. It will be a great experience to work with the great publishing house and their team. Thanks a lot Packt & Team.

I know, Java and NetBeans community will definitely accept the book with a grand welcome. The book is intended for Java Developers who are not aware of NetBeans IDE or those who have experience of Java development but have not used NetBeans for development of Java applications. This book can be referred by novice also to learn Java and Java application development using NetBeans IDE very easily.

My outline (contents) was selected out of few other authors and then after we signed the contract, now the book is complete and very soon the book will hit the market in different formats by the publisher in March 2013.

I just love it, I have tried my best in writing this book and to make it easier for novice to experts. It was a great pleasure working with Packt Team.

You will learn many things from this book such as :

Use NetBeans IDE for Java technologies
Develop a HelloWorld application with NetBeans IDE
Explore the layout of NetBeans IDE
Develop different Java applications in NetBeans
Use the Visual Designer
Design Java projects
Develop web applications using NetBeans IDE
Add and handle images in your application
Write interfaces in NetBeans IDE
Handle exceptions in NetBeans IDE
Deploy UI applications

You can order the book to avail huge discount. Instead of Packt Publishing the NetBeans IDE How-to book is also available on Amazon, Amazon UK, Barnes & Noble, Safari Books Online too.

You can buy and download the book in different formats such as e-book (pdf), e-pub, kindle book, etc.

I hope you will like the book. After reading, please mail me your reviews.

You can book your copy from following links :

Get your copy now and start developing professional applications within few minutes.

February 24, 2013 by Aatul Palandurkar Books J2EE Tutorials J2ME Tutorials Java Java Source Code Java Tutorials NetBeans NetBeans IDE Source Code NetBeans Tutorials Web Design Tutorials 4

Java Program to convert Decimal values to Hexadecimal values

Java Program to convert Decimal values to Hexadecimal values :

Java Program to Convert Decimal Number to Roman Number

Java program that converts a decimal number to Roman number. Decimal Number is accepted using Scanner class at the time of execution.

Java program that converts a decimal number to Roman number. Decimal Number is accepted as command line input at the time of execution.

Passing data between activities in Android

Code for passing data between activities in Android :

Code for passing multiple data or values between activities in Android :

Method 1 : Using Intent to pass data and Bundle to extract data between activities in Android

Method 2 : Using Bundle to pass and to extract data between activities in Android

Code for passing array between activities in Android :

Code for passing ArrayList between activities in Android :

Java Program to Convert Binary to Decimal

Java Program to convert Decimal to Binary

Java Program to find prime number upto N number

Program to find Sum of Digits in Java

Simple Interest Example in Java

7 differences between HashMap and HashTable

Book : NetBeans IDE How-to Instant

Recent Posts

Recent Comments

Archives

Categories