Prime Numbers in Java - Algorithms

Question

I have started learning to code in Java and decided I would use the Project Euler site to give me little tasks to try and complete with each bit of new coding I learn. So I came

Answer 1

A simple algorithm for factoring a composite number by trial division goes like this:

function factors(n)
    f, fs := 2, []
    while f * f <= n
        while n % f == 0
            fs.append(f)
            n := n / f
        f := f + 1
    if n > 1
        fs.append(n)
    return fs

That algorithm can be improved, and there are better algorithms for factoring large numbers, but it's sufficient for your task. When you are ready for more, I modestly recommend the essay Programming with Prime Numbers at my blog, which includes implementations of that algorithm and others in Java.