Binary search method an array using Comparable in Java

Problem:

Write a methoe that binary search an array using Comparable in Java.

Output:

Not applicable.

Solution:

public static int binarysearch(Comparable[] items, Comparable target, int first, int last)
  {
    if(first>last)
      return -1;
    else
    {
      int middle=(first+last)/2;
      int value=target.compareTo(items[middle]);
      if(value==0)
        return middle;
      else if(value>0)
        return binarysearch( items,  target,  middle+1,  last);
      else
        return binarysearch( items,  target,  first ,  middle-1);

    }