Basic Java Program Examples: Java programs are commonly requested during interviews and examinations. These programs cover various topics such as control statements, arrays, strings, object-oriented programming, and more. 

Frequently asked Java basic programs include Fibonacci series, prime numbers, factorial numbers, and palindrome numbers, among others. Each program is accompanied by multiple examples and their respective outputs. If you’re new to Java programming, it’s advisable to review our Java tutorial first. Below is a list of Java programs for your reference.

Basic Java Program Examples Overview

Java remains a dominant force in the Android world, with numerous famous applications like Google, Amazon, LinkedIn, Uber, and Spotify built using this language. To efficiently learn any programming language, practice is key. 

That’s why we have compiled many Java programs. These programs cover a wide range of topics and have been rigorously tested using the Apache NetBeans IDE. Whether you’re a beginner or an experienced programmer, this collection caters to all levels. 

Each code typically presents a basic version of the code followed by a more comprehensive implementation. 

KEY TAKEAWAYS:

• Importance of Basic Java Programs: Learning basic Java programs is essential for building a strong foundation in programming concepts such as variables, data types, loops, conditionals, and methods.
• Learning Objectives: Basic Java programs help beginners understand the syntax and structure of the Java programming language, develop problem-solving skills, and prepare for advanced topics like object-oriented programming, data structures, and algorithms.
• Hands-on Experience: Writing and executing Java programs provide hands-on experience, which is crucial for gaining proficiency in programming and eventually developing practical applications.

Basic Java Program Examples With Outputs

Here are some basic Java program examples with outputs:

1) Hello World Program:

public class HelloWorld {

 public static void main(String[] args) {

 System.out.println(“Hello, World!”);

 }

}

Output:

Hello, World!

2) Addition of Two Numbers:

public class AddNumbers {

 public static void main(String[] args) {

 int num1 = 5, num2 = 10, sum;

 sum = num1 + num2;

 System.out.println(“Sum of ” + num1 + ” and ” + num2 + ” is: ” + sum);

 }

}

Output:

Sum of 5 and 10 is: 15

3) Find Maximum of Three Numbers:

public class MaxOfThreeNumbers {

 public static void main(String[] args) {

 int num1 = 10, num2 = 20, num3 = 15, max;

 max = (num1 > num2) ? (num1 > num3 ? num1 : num3) : (num2 > num3 ? num2 : num3);

 System.out.println(“Maximum of ” + num1 + “, ” + num2 + “, and ” + num3 + ” is: ” + max);

 }

}

Output:

Maximum of 10, 20, and 15 is: 20

4) Check Even or Odd Number:

public class EvenOdd {

 public static void main(String[] args) {

 int num = 5;

 if(num % 2 == 0)

 System.out.println(num + ” is even.”);

 else

 System.out.println(num + ” is odd.”);

 }

}

Output:

5 is odd.

5) Factorial of a Number:

public class Factorial {

 public static void main(String[] args) {

 int num = 5, factorial = 1;

 for(int i = 1; i <= num; ++i) {

 factorial *= i;

 }

 System.out.println(“Factorial of ” + num + ” is: ” + factorial);

 }

}

Output:

Factorial of 5 is: 120

6) Print Pattern in Java:

public class PrintPattern {

 public static void main(String[] args) {

 int rows = 5;

 for (int i = 1; i <= rows; ++i) {

 for (int j = 1; j <= i; ++j) {

 System.out.print(“* “);

 }

 System.out.println();

 }

 }

}

Output:

* 

* * 

* * * 

* * * * 

* * * * *

7) Add Two Binary Numbers in Java:

public class AddBinaryNumbers {

 public static void main(String[] args) {

 long binary1 = 1010, binary2 = 1101;

 int i = 0, remainder = 0;

 long[] sum = new long[20];

 while (binary1 != 0 || binary2 != 0) {

 sum[i++] = (binary1 % 10 + binary2 % 10 + remainder) % 2;

 remainder = (int) (binary1 % 10 + binary2 % 10 + remainder) / 2;

 binary1 = binary1 / 10;

 binary2 = binary2 / 10;

 }

 if (remainder != 0) {

 sum[i++] = remainder;

 }

 –i;

 System.out.print(“Sum of two binary numbers: “);

 while (i >= 0) {

 System.out.print(sum[i–]);

 }

 }

}

Output:

Sum of two binary numbers: 11011

8) Add Two Complex Numbers in Java:

class Complex {

 double real, imaginary;

 Complex(double r, double i) {

 this.real = r;

 this.imaginary = i;

 }

 public static Complex add(Complex c1, Complex c2) {

 Complex temp = new Complex(0, 0);

 temp.real = c1.real + c2.real;

 temp.imaginary = c1.imaginary + c2.imaginary;

 return temp;

 }

}

public class AddComplexNumbers {

 public static void main(String[] args) {

 Complex c1 = new Complex(4.5, 5);

 Complex c2 = new Complex(2.5, 3.5);

 Complex temp = Complex.add(c1, c2);

 System.out.println(“Sum = ” + temp.real + ” + ” + temp.imaginary + “i”);

 }

}

Output:

Sum = 7.0 + 8.5i

9) Multiply Two Numbers in Java:

public class MultiplyTwoNumbers {

 public static void main(String[] args) {

 double first = 2.5, second = 4.5;

 double product = first * second;

 System.out.println(“The product is: ” + product);

 }

}

Output:

The product is: 11.25

10) Check Leap Year in Java:

public class LeapYear {

 public static void main(String[] args) {

 int year = 2024;

 if (((year % 4 == 0) && (year % 100 != 0)) || (year % 400 == 0)) {

 System.out.println(year + ” is a leap year.”);

 } else {

 System.out.println(year + ” is not a leap year.”);

 }

 }

}

Output:

2024 is a leap year.

11) Check Vowel or Consonant in Java:

public class VowelConsonant {

 public static void main(String[] args) {

 char ch = ‘A’;

 if (ch == ‘a’ || ch == ‘e’ || ch == ‘i’ || ch == ‘o’ || ch == ‘u’

 || ch == ‘A’ || ch == ‘E’ || ch == ‘I’ || ch == ‘O’ || ch == ‘U’) {

 System.out.println(ch + ” is a vowel.”);

 } else {

 System.out.println(ch + ” is a consonant.”);

 }

 }

}

Output:

A is a vowel.

12) Calculate Compound Interest in Java:

public class CompoundInterest {

 public static void main(String[] args) {

 double principal = 15000, rate = 5.5, time = 3;

 double compoundInterest = principal * (Math.pow((1 + rate / 100), time)) – principal;

 System.out.println(“Compound Interest: ” + compoundInterest);

 }

}

Output:

Compound Interest: 2653.4375

13) Java Program to Calculate Simple Interest:

import java.util.Scanner;

public class SimpleInterest {

 public static void main(String[] args) {

 Scanner input = new Scanner(System.in);

 System.out.print(“Enter principal amount: “);

 double principal = input.nextDouble();

 System.out.print(“Enter rate of interest: “);

 double rate = input.nextDouble();

 System.out.print(“Enter time period in years: “);

 double time = input.nextDouble();

 double simpleInterest = (principal * rate * time) / 100;

 System.out.println(“Simple Interest: ” + simpleInterest);

 input.close();

 }

}

Output:

Enter principal amount: 5000

Enter rate of interest: 2.5

Enter time period in years: 3

Simple Interest: 375.0

14) Java Program to Find Quotient and Remainder:

import java.util.Scanner;

public class QuotientRemainder {

 public static void main(String[] args) {

 Scanner input = new Scanner(System.in);

 System.out.print(“Enter dividend: “);

 int dividend = input.nextInt();

 System.out.print(“Enter divisor: “);

 int divisor = input.nextInt();

 int quotient = dividend / divisor;

 int remainder = dividend % divisor;

 System.out.println(“Quotient: ” + quotient);

 System.out.println(“Remainder: ” + remainder);

 input.close();

 }

}

Output:

Enter dividend: 17

Enter divisor: 5

Quotient: 3

Remainder: 2

15) Java Program to Calculate Power of a Number:

import java.util.Scanner;

public class PowerOfNumber {

 public static void main(String[] args) {

 Scanner input = new Scanner(System.in);

 System.out.print(“Enter base: “);

 int base = input.nextInt();

 System.out.print(“Enter exponent: “);

 int exponent = input.nextInt();

 long result = 1;

 while (exponent != 0) {

 result *= base;

 –exponent;

 }

 System.out.println(“Result: ” + result);

 input.close();

 }

}

Output:

Enter base: 3

Enter exponent: 4

Result: 81

16) Java Program to Convert char to String and String to Char:

public class CharStringConversion {

 public static void main(String[] args) {

 // Convert char to String

 char ch = ‘A’;

 String str = Character.toString(ch);

 System.out.println(“Char to String: ” + str);

 // Convert String to char

 String s = “Hello”;

 char c = s.charAt(0);

 System.out.println(“String to Char: ” + c);

 }

}

17) Java Program to Find Duplicate Characters in a String:

import java.util.HashMap;

import java.util.Map;

public class DuplicateCharacters {

 public static void main(String[] args) {

 String str = “programming”;

 Map charCountMap = new HashMap<>();

 for (char ch : str.toCharArray()) {

 if (charCountMap.containsKey(ch)) {

 charCountMap.put(ch, charCountMap.get(ch) + 1);

 } else {

 charCountMap.put(ch, 1);

 }

 }

 System.out.println(“Duplicate Characters:”);

 for (Map.Entry entry : charCountMap.entrySet()) {

 if (entry.getValue() > 1) {

 System.out.println(entry.getKey() + ” – ” + entry.getValue() + ” times”);

 }

 }

 }

}

18) Java Program to Check Palindrome String using Stack, Queue, For, and While loop:

import java.util.LinkedList;

import java.util.Queue;

import java.util.Stack;

public class PalindromeCheck {

 public static void main(String[] args) {

 String str = “racecar”;

 Stack stack = new Stack<>();

 Queue queue = new LinkedList<>();

 for (char ch : str.toCharArray()) {

 stack.push(ch);

 queue.add(ch);

 }

 boolean isPalindrome = true;

 while (!stack.isEmpty() && !queue.isEmpty()) {

 if (!stack.pop().equals(queue.remove())) {

 isPalindrome = false;

 break;

 }

 }

 if (isPalindrome) {

 System.out.println(str + ” is a palindrome.”);

 } else {

 System.out.println(str + ” is not a palindrome.”);

 }

 }

}

19) Java Program to Sort Strings in Alphabetical Order:

import java.util.Arrays;

public class SortStrings {

 public static void main(String[] args) {

 String[] strings = {“orange”, “apple”, “banana”, “grape”};

 Arrays.sort(strings);

 System.out.println(“Sorted Strings:”);

 for (String s : strings) {

 System.out.println(s);

 }

 }

}

20) Java Program to Reverse Words in a String:

public class ReverseWords {

 public static void main(String[] args) {

 String str = “Hello World”;

 String[] words = str.split(” “);

 StringBuilder reversed = new StringBuilder();

 for (int i = words.length – 1; i >= 0; i–) {

 reversed.append(words[i]).append(” “);

 }

 System.out.println(“Reversed Words: ” + reversed.toString().trim());

 }

}

21) Java Program to perform bubble sort on Strings:

import java.util.Arrays;

public class BubbleSortStrings {

 public static void main(String[] args) {

 String[] arr = {“banana”, “apple”, “orange”, “grapes”, “pineapple”};

 bubbleSort(arr);

 System.out.println(“Sorted Array: ” + Arrays.toString(arr));

 }

 public static void bubbleSort(String[] arr) {

 int n = arr.length;

 for (int i = 0; i < n – 1; i++) {

 for (int j = 0; j < n – i – 1; j++) {

 if (arr[j].compareTo(arr[j + 1]) > 0) {

 // swap arr[j] and arr[j+1]

 String temp = arr[j];

 arr[j] = arr[j + 1];

 arr[j + 1] = temp;

 }

 }

 }

 }

}

Output:

Sorted Array: [apple, banana, grapes, orange, pineapple]

22) Java program to find occurrence of a character in a String:

public class CharacterOccurrences {

 public static void main(String[] args) {

 String str = “hello world”;

 char ch = ‘o’;

 int count = 0;

 for (int i = 0; i < str.length(); i++) {

 if (str.charAt(i) == ch) {

 count++;

 }

 }

 System.out.println(“Occurrences of ‘” + ch + “‘ in the string: ” + count);

 }

}

Output:

Occurrences of ‘o’ in the string: 2

23) Java program to count vowels and consonants in a String:

public class VowelsConsonantsCount {

 public static void main(String[] args) {

 String str = “hello world”;

 int vowels = 0, consonants = 0;

 str = str.toLowerCase();

 for (int i = 0; i < str.length(); i++) {

 char ch = str.charAt(i);

 if (ch == ‘a’ || ch == ‘e’ || ch == ‘i’ || ch == ‘o’ || ch == ‘u’) {

 vowels++;

 } else if (ch >= ‘a’ && ch <= ‘z’) {

 consonants++;

 }

 }

 System.out.println(“Vowels: ” + vowels);

 System.out.println(“Consonants: ” + consonants);

 }

}

Output:

Vowels: 3

Consonants: 7

24) Java Program to check two strings are anagram or not:

import java.util.Arrays;

public class AnagramCheck {

 public static void main(String[] args) {

 String str1 = “listen”;

 String str2 = “silent”;

 boolean isAnagram = checkAnagram(str1, str2);

 if (isAnagram) {

 System.out.println(str1 + ” and ” + str2 + ” are anagrams.”);

 } else {

 System.out.println(str1 + ” and ” + str2 + ” are not anagrams.”);

 }

 }

 public static boolean checkAnagram(String str1, String str2) {

 if (str1.length() != str2.length()) {

 return false;

 }

 char[] chars1 = str1.toCharArray();

 char[] chars2 = str2.toCharArray();

 Arrays.sort(chars1);

 Arrays.sort(chars2);

 return Arrays.equals(chars1, chars2);

 }

}

Output:

listen and silent are anagrams.

25) Java Program to divide a string in ‘n’ equal parts:

public class DivideString {

 public static void main(String[] args) {

 String str = “abcdefghi”;

 int n = 3;

 int len = str.length();

 int partLength = len / n;

 int extraChars = len % n;

 int start = 0;

 for (int i = 0; i < n; i++) {

 int end = start + partLength + (i < extraChars ? 1 : 0);

 String part = str.substring(start, end);

 System.out.println(“Part ” + (i + 1) + “: ” + part);

 start = end;

 }

 }

}

Output:

Part 1: abc

Part 2: def

Part 3: ghi

26) Java Program to find all subsets of a string:

import java.util.ArrayList;

import java.util.List;

public class SubsetsOfString {

 public static void main(String[] args) {

 String str = “abc”;

 List subsets = new ArrayList<>();

 generateSubsets(str, 0, “”, subsets);

 System.out.println(“All subsets of ”” + str + “”: ” + subsets);

 }

 private static void generateSubsets(String str, int index, String current, List subsets) {

 if (index == str.length()) {

 subsets.add(current);

 return;

 }

 generateSubsets(str, index + 1, current + str.charAt(index), subsets);

 generateSubsets(str, index + 1, current, subsets);

 }

}

Output:

All subsets of “abc”: [, c, b, bc, a, ac, ab, abc]

27) Java Program to find longest substring without repeating characters:

import java.util.HashSet;

import java.util.Set;

public class LongestSubstringWithoutRepeating {

 public static void main(String[] args) {

 String str = “abcabcbb”;

 System.out.println(“Longest substring without repeating characters: ” + longestSubstring(str));

 }

 public static int longestSubstring(String s) {

 Set set = new HashSet<>();

 int left = 0, right = 0, maxLen = 0;

 while (right < s.length()) {

 if (!set.contains(s.charAt(right))) {

 set.add(s.charAt(right++));

 maxLen = Math.max(maxLen, set.size());

 } else {

 set.remove(s.charAt(left++));

 }

 }

 return maxLen;

 }

}

Output:

Longest substring without repeating characters: 3

28) Java Program to find longest repeating sequence in a string:

public class LongestRepeatingSequence {

 public static void main(String[] args) {

 String str = “aabcaabdaab”;

 System.out.println(“Longest repeating sequence: ” + longestRepeatingSequence(str));

 }

 public static String longestRepeatingSequence(String str) {

 int n = str.length();

 int[][] dp = new int[n + 1][n + 1];

 int longest = 0, endIndex = 0;

 for (int i = 1; i <= n; i++) {

 for (int j = i + 1; j <= n; j++) {

 if (str.charAt(i – 1) == str.charAt(j – 1) && dp[i – 1][j – 1] < (j – i)) {

 dp[i][j] = dp[i – 1][j – 1] + 1;

 if (dp[i][j] > longest) {

 longest = dp[i][j];

 endIndex = i;

 }

 } else {

 dp[i][j] = 0;

 }

 }

 }

 return str.substring(endIndex – longest, endIndex);

 }

}

Output:

Longest repeating sequence: aab

29) Java Program to remove all the white spaces from a string:

public class RemoveWhiteSpaces {

 public static void main(String[] args) {

 String str = “This is a test string”;

 String trimmedStr = removeWhiteSpaces(str);

 System.out.println(“String after removing white spaces: ”” + trimmedStr + “””);

 }

 public static String removeWhiteSpaces(String str) {

 return str.replaceAll(“\s”, “”);

 }

}

Output:

String after removing white spaces: “Thisisateststring”

30) Program to find number of elements in an array:

public class ArrayLength {

 public static void main(String[] args) {

 int[] array = {1, 2, 3, 4, 5};

 int length = array.length;

 System.out.println(“Number of elements in the array: ” + length);

 }

}

Output:

Number of elements in the array: 5

31) Java Program to Calculate average of numbers using Array:

public class AverageOfArray {

 public static void main(String[] args) {

 int[] array = {5, 10, 15, 20, 25};

 int sum = 0;

 for (int num : array) {

 sum += num;

 }

 double average = (double) sum / array.length;

 System.out.println(“Average of numbers in the array: ” + average);

 }

}

Output:

Average of numbers in the array: 15.0

32) Java Program to Add the elements of an Array:

public class ArraySum {

 public static void main(String[] args) {

 int[] array = {1, 2, 3, 4, 5};

 int sum = 0;

 for (int num : array) {

 sum += num;

 }

 System.out.println(“Sum of elements in the array: ” + sum);

 }

}

Output:

Sum of elements in the array: 15

33) Java Program to reverse an array:

import java.util.Arrays;

public class ReverseArray {

 public static void main(String[] args) {

 int[] array = {1, 2, 3, 4, 5};

 reverseArray(array);

 System.out.println(“Reversed array: ” + Arrays.toString(array));

 }

 public static void reverseArray(int[] array) {

 int start = 0;

 int end = array.length – 1;

 while (start < end) {

 int temp = array[start];

 array[start] = array[end];

 array[end] = temp;

 start++;

 end–;

 }

 }

}

Output:

Reversed array: [5, 4, 3, 2, 1]

34) Java Program to sort an array in ascending order:

import java.util.Arrays;

public class SortArray {

 public static void main(String[] args) {

 int[] array = {5, 3, 9, 1, 7};

 Arrays.sort(array);

 System.out.println(“Sorted array in ascending order: ” + Arrays.toString(array));

 }

}

Output:

Sorted array in ascending order: [1, 3, 5, 7, 9]

35) Java Program to convert char Array to String:

public class CharArrayToString {

 public static void main(String[] args) {

 char[] charArray = {‘h’, ‘e’, ‘l’, ‘l’, ‘o’};

 String str = new String(charArray);

 System.out.println(“Converted String: ” + str);

 }

}

Output:

Converted String: hello

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Why Learn Basic Java Program Examples

Learning basic Java program examples is important for several reasons:

• Foundation Building: Basic Java programs help in building a strong foundation in programming concepts such as variables, data types, loops, conditionals, and methods.
• Understanding Syntax: By practicing basic Java programs, learners become familiar with the syntax and structure of the Java programming language.
• Problem Solving Skills: Basic Java programs often involve solving simple problems, which helps in developing problem-solving skills and logical thinking.
• Preparation for Advanced Topics: Basic Java programs serve as a stepping stone for learning more advanced topics such as object-oriented programming, data structures, and algorithms.
• Hands-on Experience: Writing and executing Java programs provide hands-on experience, which is essential for gaining proficiency in programming.
• Application Development: Many real-world applications are built using Java, so learning basic Java programs lays the groundwork for developing practical applications in the future.

Overall, learning basic Java program examples is crucial for beginners to grasp the fundamentals of Java programming and progress towards becoming proficient developers.

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