Prime Number Counter in Java

primecounter.java

/*
I was able to achieve these speeds on my laptop: Intel Core i7-4500U @ 1.80GHZ
Test 1: 664579    took 56ms
Test 2: 5761455   took 702ms
Test 3: 50847534  took 9.062s
*/

public class PrimeCounter {
	public static void main(String[] args) {		
		int[] times = new int[]{10000000, 100000000, 1000000000};
		
		for (int i = 0; i < times.length; i++) {
			long start = System.currentTimeMillis();
			int num = countPrimes(times[i]);
			long elapsed = System.currentTimeMillis() - start;
			System.out.println("Test " + (i+1) + ": " + num +"\t took " + elapsed);
		}
	}
	
	public static int countPrimes(int limit) {
		// Return if less than 1
		if (limit <= 1) {
			return 0;
		}
		
		// Get the sqrt of the limit
		double sqrtLimit = Math.sqrt(limit);
	 
		// Create array
		boolean[] numbers = new boolean[limit];
		
		// Set 1 to prime
		numbers[0] = true;
		int numPrimes = 0;
		
		// Count the number of olds
		if (limit%2 == 0) {
			numPrimes = limit / 2;
		} else {
			numPrimes = (limit + 1) / 2;
		}
	 
		for (int i = 3; i <= sqrtLimit; i+=2) {
			if (!numbers[i]) {
				for (int j = i * i; j < limit; j += i * 2) {
					if (!numbers[j]) {
						numbers[j] = true;
						numPrimes -= 1;
					}
				}
			}
		}
	 
		return numPrimes;
	}
}