How to check whether a number is a prime number or not in java?

A Prime number is a number that is divisible by only 1 and itself. A prime number canโ€™t be divided by zero, because numbers divided by zero are undefined. The smallest prime number is 2, which is also the only even prime.

Letโ€™s see the logic to check whether a number is a prime number or not,

Solution

PrimeNumber.java

package com.javacodepoint.programs;

import java.util.Scanner;

public class PrimeNumber {

	public static void main(String[] args) {

		System.out.print("Enter an integer number:");

		// Reading user input using Scanner object
		int number = new Scanner(System.in).nextInt();
		
		if(number > 1 && checkPrime(number)) {
			System.out.println("The given number is a prime number.");
		}else {
			System.out.println("The given number is not a prime number.");
		}

	}
	
	/*
	 * Method to check whether number is prime or not
	 */
	
	public static boolean checkPrime(int number) {
		
		boolean isPrime = true;
		
		for(int i=2; i <= (number/2); i++ ) {
			
			if(number % i == 0) {
				isPrime = false;
				break;
			}
			
		}
		
		return isPrime;
		
	}
}

OUTPUT:

Enter an integer number:13
The given number is a prime number.

Java logical programs list


Java Basic Programs

Java String Programs

Java Miscellaneous Programs