Java – project Euler: procedural optimization of question 7?

So I call myself a fairly novice programmer because I mainly focus on my school hardware rather than many computer science courses

So I solved the problem 7 of Euler project:

I managed to solve this problem in Java without a problem, but when I ran my solution, it took 8 and changed the number of seconds I want to know how to optimize this from a programming point of view, not a mathematical point of view

Are array loops and while statements mainly processing time consuming? How can this be optimized? Again, don't look for a strange mathematical equation... There are many in the solution thread

Spoiler my solution is as follows

public class PrimeNumberList {

private ArrayList<BigInteger> primesList = new ArrayList<BigInteger>();

public void fillList(int numberOfPrimes) {
    primesList.add(new BigInteger("2"));
    primesList.add(new BigInteger("3"));
    while (primesList.size() < numberOfPrimes){
        getNextPrime();
    }
}

private void getNextPrime() {
    BigInteger lastPrime = primesList.get(primesList.size()-1);
    BigInteger currentTestNumber = lastPrime;
    BigInteger modulusResult;
    boolean prime = false;
    while(!prime){
        prime = true;
        currentTestNumber = currentTestNumber.add(new BigInteger("2"));
        for (BigInteger bi : primesList){
            modulusResult = currentTestNumber.mod(bi);
            if (modulusResult.equals(BigInteger.ZERO)){
                prime = false;
                break;
            }
        }
        if(prime){
            primesList.add(currentTestNumber);
        }
    }
}

public BigInteger get(int primeTerm) {
    return primesList.get(primeTerm - 1);
}

}

Solution

Since the 10001st prime is not so large, you can use long instead of BigInteger BigInteger instance is a mature Java object. There will be a lot of overhead when creating and operating them