codewars022: Pure odd digits primes

https://www.codewars.com/kata/55e0a2af50adf50699000126/train/java

package codewars;
//--https://www.codewars.com/kata/55e0a2af50adf50699000126/train/java
public class OddDigPrime{
  public static Boolean isPrime(long num){
    for(long i=2; i <= Math.sqrt(num); i++){
      if(num % i == 0){
        return false;
      }
    }
    return true;
  }
  public static Boolean onlyOddDig(long num){
    long temp = -1;
    while(num > 0){
      temp = num % 10;
      if(temp % 2 == 0){
        return false;
      }
      num = num / 10;
    }
    return true;
  }
  public static long[] onlyOddDigPrimes(long n){
    List<Long> list = new ArrayList<Long>();
    for(long i=3; i <= n; i++){
      if(OddDigPrime.isPrime(i) && onlyOddDig(i)){
        list.add(i);
      }
    }
    long temp = n + 1;
    long next = 0;
    while(true){
      if(OddDigPrime.isPrime(temp) && onlyOddDig(temp)){
        next = temp;
        break;
      }
      temp++;
    }
    if(n == list.get(list.size() - 1)){
      return new long[] {(long)list.size(), n, next};
    }else{
      return new long[] {(long)list.size(), list.get(list.size() - 1), next};
    }
  }
}

Ref:

http://www.jb51.net/article/48970.htm

https://zhidao.baidu.com/question/325009462.html