Project Euler #3 takes forever in Java

Question

Problem #3 on Project Euler is:

The prime factors of 13195 are 5, 7, 13 and 29.

What is the largest prime factor of the number 60085147514

Answer 1

public HashSet distinctPrimeFactors(int n) //insane fast prime factor generator
{
    HashSet factors = new HashSet();
    int lastres = n;
    if (n==1)
    {
        factors.add(1);
        return factors;
    }
    while (true)
    {
        if (lastres==1)
            break;
        int c = 2;
        while (true)
        {
            if (lastres%c==0)
                break;
            c++;
        }
        factors.add(c);
        lastres/=c;
    }
    return factors;
}

If you want to generate distinct prime factors for a number quickly use this method which makes the number smaller on each iteration. You can change int to long and it should work for you.