Test.java

package test;

public class Test {

    public static void main(String[] args) throws Exception {
        int[] ns = {1_000_000, 5_000_000, 10_000_000, 25_000_000, 50_000_000, 100_000_000, 500_000_000};
        for (int n : ns) {
            for (int counter = 5; counter --> 0;) {
                float[] a = new float[n];
                for (int i = 0; i < n; i++)
                    a[i] = (float) Math.random();

                long t_start = System.currentTimeMillis();

                for (int i = 0; i < a.length; i++)
                    a[i] = a[i] >= 0.5 ? 1.0f : 0.0f;

                long elapsed = System.currentTimeMillis() - t_start;
                System.out.printf("%10d %6d%n", n, elapsed);
                System.gc();
            }
        }
    }

}