Example of strange Java behavior

Timing.java

import static java.lang.System.currentTimeMillis;

import java.util.Arrays;
import java.util.Random;

public class Sandbox
{
	public static final Random RANDOM = new Random();
	
	public static double sumWith = 0;
	public static double sumWithout = 0;
	public static double t0 = 0;


	public static void main(String[] args)
	{
		int size = 100;

		for(int i = 0; i < 20000; i++)
		{						
			int[] a = new int[size];
			int[] b = new int[size];
			
			for(int j = 0; j < size; j++)
			{
				a[j] = RANDOM.nextInt(size * 100);
				b[j] = RANDOM.nextInt(size * 100);
				
				Arrays.sort(a);
				Arrays.sort(b);
			}
			
			t0 = System.nanoTime();
			with(a, b);
			sumWith += System.nanoTime() - t0;
			
			t0 = System.nanoTime();
			without(a, b);
			sumWithout += System.nanoTime() - t0;
		}
		
		System.out.println("time with:    " + sumWith + " ns.");
		System.out.println("time without: " + sumWithout + " ns.");
	}
	
	public static int with(int[] a, int[] b)
	{
		int i = 0, j = 0;
		
		int res = 0;

		while(i < a.length && j < b.length)
		{
			if(a[i] > b[j])
				j ++;
			else if(a[i] < b[j])
				i ++;
			else if(a[i] == b[j]) // ?
			{
				res ++;
				i ++;
				j ++;
			}
		}
		
		return res;
	}

	public static int without(int[] a, int[] b)
	{
		int i = 0, j = 0;
		
		int res = 0;

		while(i < a.length && j < b.length)
		{
			if(a[i] > b[j])
				j ++;
			else if(a[i] < b[j])
				i ++;
			else // if(a[i] == b[j]) 
			{
				res ++;
				i ++;
				j ++;
			}
		}
		
		return res;
	}
}