Palindrome String Example in Java

Introduction

Palindrome String is a classic Java console program that demonstrates the concept with complete source code and sample output. Calculation programs apply formulas to solve geometry, statistics and numeric problems.

This tutorial walks through the program line by line, explains how the logic works, and highlights best practices you can apply in your own code.

Definition

A palindrome is a word, phrase, number, or other sequence of characters which reads the same backward or forward. Allowances may be made for adjustments to capital letters, punctuation, and word dividers. Famous examples include “A man, a plan, a canal, Panama!”

Palindrome String Example Program

import java.util.*;
class PalindromeString{
	public static void main(String args[]){
		String str1,str2= "";
		Scanner in = new Scanner(System.in);
		System.out.println("Enter the string");
		str1= in.nextLine();
		int length = str1.length();
		for ( int i = length - 1; i >= 0; i-- ){
			str2 = str2 + str1.charAt(i);
		}
		if (str1.equals(str2)){
			System.out.println("The given string is a palindrome.");
		}
		else{
			System.out.println("The given string is not a palindrome.");
		}
	}	
}

Sample Output

Enter the string
madam
The given string is a palindrome.

When to use

Use these formulas in homework tools, engineering calculators or anywhere repeated numeric computation is needed.

How it works

1. Execution begins in the main method — the JVM calls this method when you run the class.

2. import java.util.*; imports a class used later in the program.

3. String str1,str2= ""; updates a variable used in the calculation or output.

4. A Scanner reads typed input from the keyboard (System.in).

5. A println / print call writes text to the console — part of the sample output below.

6. str1= in.nextLine(); updates a variable used in the calculation or output.

7. int length = str1.length(); updates a variable used in the calculation or output.

8. The if statement runs the nested code only when the condition is true.

Best Practices

Common Mistakes