Happy Number

public class Solution {
    public boolean isHappy(int n) {
        int sum=0;
         if(n==1||n==7)
            return true;
         else if(n>1&&n<9)
            return false;
        while(n>0){
            sum+=(n%10)*(n%10);
            n/=10;
        }
        return isHappy(sum);
        
    }
}