Prime, Divisor, Search

public class Main {
    public static int is_it_prime(int x){
        for(int i = 1; i <= x/2; i++){
            if(x%2 == 0){
                return 0;
            }
        }
        return 1;
    }
    public static void main(String[] args) {
        if(is_it_prime(31) == 1){
            System.out.println("yes");
        }else{
            System.out.println("no");
        }
    }
}

package com.company;

import java.util.Arrays;
import java.util.List;

public class Main {
    public static int search_number(Integer x, List<Integer> list){
        for(int i = 0; i < list.size(); i++){
            if(list.get(i) == x){
                return 1;
            }
        }
        return  0;
    }
    public static void main(String[] args) {
        List<Integer> list = Arrays.asList(1, 3, 12, 99, 204, 909876);

        if(search_number(7, list) == 1){
            System.out.println("Found the number");
        }
        else{
            System.out.println("Not Found");
        }
    }
}

package com.company;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class Main {
    public static List<Integer> common_divisor(Integer x, Integer y){
        Integer max = Math.max(x, y);
        Integer min = Math.min(x, y);
        var list = new ArrayList<Integer>();
        for(int i = 1; i <= min; i++){
            if((max%i == 0 && min%i == 0) == true){
                list.add(i);
            }
        }
        return list;
    }
    public static void main(String[] args) {
        System.out.println(common_divisor(12, 24));
    }
}