Hello everyone, my java solution below for the Happy Number problem keeps giving me a stack overflow error. I am unable to understand why.

'''
class Solution {
public boolean isHappy(int n) {
if (n == 1){
return true;
} else if (n < 10){
return false;
} else{
String x = Integer.toString(n);
int sum = 0;
for (int i = 0; i < x.length(); i++){
sum += Math.pow((int)x.charAt(i), 2);
return isHappy(sum);
}
} return false;
}
}
'''