BigInteger nextProbablePrime() Method in Java with Examples

The java.math.BigInteger.nextProbablePrime() is used to find the first integer greater than this BigInteger that is probably prime. If this method returns ‘p’ then there is no prime number ‘q’ between this Biginteger and ‘p’ (this < q < p ) i.e. it never skips any prime number greater than BigInteger that is used to call the method.

Syntax:

public BigInteger nextProbablePrime()

Parameters: The method doesn’t accept any Parameters.
Return: This method returns a Biginteger which holds the first integer greater than this BigInteger that is probably prime number.

Exception: The number must be non – negative and not too large otherwise Arithmetic Exception is thrown.

Below programs illustrate nextProbablePrime() method of BigInteger class

Example 1:

// Java program to demonstrate
// nextProbablePrime() method of BigInteger

import java.math.BigInteger;

public class GFG {
    public static void main(String[] args)
    {

        // BigInteger object to store the result
        BigInteger result;

        // For user input
        // Use Scanner or BufferedReader

        // object of String created
        // Holds the value to find next prime number
        String input1 = "1516132";

        // Creating BigInteger object
        BigInteger a
            = new BigInteger(input1);

        // Using nextProbablePrime()
        result = a.nextProbablePrime();

        // Print result
        System.out.println("The next probable"
                           + " Prime number is "
                           + result);
    }
}

Output:

The next probable Prime number is 1516153

Example 2: Printing all Prime number below 100

// Java program to demonstrate
// nextProbablePrime() method of BigInteger

import java.math.BigInteger;

public class GFG {
    public static void main(String[] args)
    {

        // BigInteger object to store the result
        BigInteger result;

        // Creating BigInteger objects
        BigInteger a;

        // Printing all prime numbers
        // Below 100
        for (int i = 0; i < 100😉 {
            a = new BigInteger(
                Integer.toString(i));

            // Using nextProbablePrime()
            result = a.nextProbablePrime();

            // Print the answer
            if (Integer.parseInt(
                    result.toString())
                < 100) {
                System.out.print(result + " ");
            }

            i = Integer.parseInt(
                result.toString());
        }
    }
}

Output:

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

Example 3: Program showing exception when value is negative.

// Java program to demonstrate
// nextProbablePrime() method of BigInteger

import java.math.BigInteger;

public class GFG {
    public static void main(String[] args)
    {

        // BigInteger object to store the result
        BigInteger result;

        // For user input
        // Use Scanner or BufferedReader

        // object of String created
        // Holds the value to find prime number
        String input1 = "-5";

        // Creating BigInteger objects
        BigInteger a
            = new BigInteger(input1);

        try {
            // Using nextProbablePrime()
            result = a.nextProbablePrime();
        }
        catch (ArithmeticException e) {
            System.out.println(e);
        }
    }
}

Output:

java.lang.ArithmeticException: start < 0: -5

To know about checking current BigInteger is prime or not, visit isProbablePrime() Method in Java page.

Reference: https://docs.oracle.com/en/java/javase/12/docs/api/java.base/java/math/BigInteger.html#nextProbablePrime()