Java.math.BigInteger.probablePrime() method in Java (original) (raw)

Last Updated : 11 Jul, 2025

Prerequisite : BigInteger BasicsThe probablePrime() method will return a Biginteger of bitLength bits which is prime. bitLength is provided as parameter to method probablePrime() and method will return a prime BigInteger of bitLength bits. The probability that a BigInteger returned by this method is composite and does not exceed 2^-100.Syntax:

public static BigInteger probablePrime(int bitLength, Random rnd)

Parameters: This method accepts two parameters as shown in the above syntax and described below.

• bitLength - bitLength of the returned BigInteger.
• rnd - source of random bits used to select candidates to be tested for primality.

Return Value: This method returns a BigInteger of bitLength bits that is probably prime.Exception:

• ArithmeticException - if bitLength < 2.

Below program illustrate the probablePrime() method:

Java `

import java.math.*; import java.util.Random; import java.util.Scanner;

public class GFG {

public static void main(String[] args)
{

    Scanner sc = new Scanner(System.in);

    // create a BigInteger object
    BigInteger biginteger;

    // create a integer value for bitLength
    int length = 4;

    // create a random object
    Random random = new Random();

    // call probablePrime method to find next probable prime
    // whose bit length is equal to bitLength provided as parameter.
    biginteger = BigInteger.probablePrime(length, random);

    String result = "ProbablePrime whose bit length is "
                    + length + " = " + biginteger;

    // print result value
    System.out.println(result);
}

}

`

Output:

ProbablePrime whose bit length is 4 = 13

Reference:https://docs.oracle.com/javase/7/docs/api/java/math/BigInteger.html#probablePrime(int, %20java.util.Random)