Let’s learn prime number program in java and java program to display prime numbers from 1 to 100.

Java program to find prime numbers is most common java interview question.

#### Java program to display prime numbers from 1 to 100

A prime number is one which is divisible by 1 and itself. Here’s the prime number from 1 to 100 program in java,

Also read – java program to check whether number is prime or not

// java code for prime number public class PrimeNumbersJava { public static void main(String[] args) { int a = 0; int number = 0; String strPrimeNumber = ""; for(a = 1; a <= 100; a++) { int counter = 0; for(number = a; number >= 1; number--) { if(a % number == 0) { counter = counter + 1; } } if(counter == 2) { strPrimeNumber = strPrimeNumber + a + " "; } } System.out.println("Prime numbers from 1 to 100 : "); System.out.println(strPrimeNumber); } }

**Output:**

Prime numbers from 1 to 100 : 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97

Similarly we can display from 1 to n. Here’s the java code for prime number,

import java.util.Scanner; public class PrimeNumber { public static void main(String[] args) { Scanner sc = new Scanner(System.in); int a = 0; int number = 0; String strPrimeNumber = ""; System.out.println("Please enter the value of n : "); int n = sc.nextInt(); for(a = 1; a <= n; a++) { int count = 0; for(number = a; number >= 1; number--) { if(a % number == 0) { count = count + 1; } } if(count == 2) { strPrimeNumber = strPrimeNumber + a + " "; } } System.out.println("Prime numbers from 1 to n : "); System.out.println(strPrimeNumber); sc.close(); } }

**Output:**

Please enter the value of n : 200

Prime numbers from 1 to n :

2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97 101 103 107 109 113 127 131 137 139 149 151 157 163 167 173 179 181 191 193 197 199