Write a Java program to find the sum of all prime numbers up to a given number.

Here’s a Java program to find the sum of all prime numbers up to a given number:

import java.util.Scanner;

public class SumOfPrimes {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("Enter a number: ");
        int num = scanner.nextInt();
        int sumOfPrimes = findSumOfPrimes(num);
        System.out.println("Sum of prime numbers up to " + num + ": " + sumOfPrimes);
    }

    public static int findSumOfPrimes(int num) {
        int sum = 0;
        for (int i = 2; i <= num; i++) {
            if (isPrime(i)) {
                sum += i;
            }
        }
        return sum;
    }

    public static boolean isPrime(int num) {
        if (num <= 1) {
            return false;
        }
        for (int i = 2; i <= Math.sqrt(num); i++) {
            if (num % i == 0) {
                return false;
            }
        }
        return true;
    }
}

In this program, we first take user input for a number. We then call the `findSumOfPrimes()` method to find the sum of all prime numbers up to the given number.

The `findSumOfPrimes()` method takes an integer `num` as a parameter and returns the sum of all prime numbers up to `num`. We initialize an integer variable `sum` to 0. We use a for loop to iterate over each number from 2 to `num`. For each number, we check if it is a prime number using the `isPrime()` method. If it is a prime number, we add it to `sum`. We then return `sum`.

The `isPrime()` method takes an integer `num` as a parameter and returns a boolean indicating whether `num` is a prime number or not. We first check if `num` is less than or equal to 1, in which case it cannot be a prime number. We then use a for loop to check if `num` is divisible by any number from 2 to the square root of `num`. If it is divisible by any number, then it is not a prime number. Otherwise, it is a prime number.

At the end of the program, we print out the sum of prime numbers up to the given number.