problems with mergeSort, help please

[Yotam Ohayon]

hi, i've written a little version of merge sort. it's a little different then what i've seen but should work the same. for some reason, if the array i'm trying to sort has more then 4 values it just replaces the right half with the left half (work fine up to 4 values, weird). i've checked my merge() method several times and it's okay, and i tried debugging my sort method more then once but cuoldn't figure out my error. could it has something to do with the fact that i've used static methods?
anyway, here's the code i've written:

public class Search {

	public static void main(String[] args) {
	int[] ar4 = {5,3,7,8,3,4,5,1};
		for(int i=0; i<ar4.length; i++)
			System.out.print(ar4[i]+",");
		System.out.println();
		int[] sorted = sort(ar4);
		for(int i=0; i<sorted.length; i++)
			System.out.print(sorted[i]+",");
		System.out.println();
	}

	private static int[] merge(int[] ar, int[] ar2) {
		int result[] = new int[ar.length+ar2.length];
		int counter=0;
		int i=0, j=0;
		while (i<ar.length && j<ar2.length){
			if (ar[i]<ar2[j])
				result[counter++]=ar[i++];
			
			else
				result[counter++]=ar2[j++];
		}
		while (j<ar2.length) 
			result[counter++]=ar2[j++];
		while (i<ar.length) 
			result[counter++]=ar[i++];
		return result;
	}

	private static int[] sort(int[] ar) {
		if (ar.length==1)
			return ar;
		int half=(ar.length/2);
		int[] left = new int[half];
		int[] right = new int[ar.length-half];
		System.arraycopy(ar, 0, left, 0, half);
		System.arraycopy(ar, half, right, 0, ar.length-half);
		sort(left);
		sort(right);
		return merge(left,right); 
	}

}

[Rob Spoor]

sort doesn't modify its arguments. Therefore, at the bottom of the sort method, you ignore the actual results from the two calls to sort. I've got your code working by changing those two lines:

left = sort(left);
right = sort(right);

[Yotam Ohayon]

hm
i feel stupid. thatnk you!

[Rob Spoor]

You're welcome.