Merge Sort in Java

mergesort.java

import java.io.*;

class Ideone
{
	static int[] slice(int[] arr, int start, int end)
	{
		int[] result = new int[end-start];
		for(int i = 0; i < result.length; i ++)
		{
			result[i] = arr[start+i];
		}
		return result;
	}
	
	static void printArray(int[] arr)
	{
		for(int i = 0;i < arr.length; i++)
		{
			System.out.print(arr[i]);
			System.out.print(" ");
		}
		System.out.println();
	}
	
	static int[] mergesort(int[] arr)
	{
		if(arr.length <= 1)
		{
			return arr;
		}
		int mid = arr.length / 2;
		int[] left = slice(arr,0,mid);
		int[] right = slice(arr,mid,arr.length);
		left = mergesort(left);
		right = mergesort(right);
		return merge(left,right);
	}
	
	static int[] merge(int[] left, int[] right)
	{
		int[] result = new int[left.length + right.length];
		int result_index = 0;
		int left_index = 0,right_index = 0;
		while(left_index < left.length && right_index < right.length)
		{
			if(left[left_index] < right[right_index])
			{
				result[result_index] = left[left_index];
				result_index += 1;
				left_index += 1;
			}
			else
			{
				result[result_index] = right[right_index];
				result_index += 1;
				right_index += 1;
			}
		}
		while(left_index < left.length)
		{
			result[result_index] = left[left_index];
			result_index += 1;
			left_index += 1;
		}
		while(right_index < right.length)
		{
			result[result_index] = right[right_index];
			result_index += 1;
			right_index += 1;
		}
		return result;
	}
	
	public static void main (String[] args)
	{
		int[] arr = {6,5,1,3,2,4};
		printArray(mergesort(arr));
	}
}