Not quite sure, but am assuming that the problem is with the long division here:

for(int i=0;i<n;i++){
   if (ans%a[i]==0) continue;
   long lifesaver = gcd(a[i],ans);
   ans *= (a[i]/lifesaver);  //O(n^2)
}

I've read this about why long division has a high complexity: https://stackoverflow.com/questions/2486152/how-is-schoolbook-long-division-an-on2-algorithm

please share other Java solutions that got accepted so we can try to compare those solutions.