Re: How do I rewrite this in a cleaner way?

I rewrote it like this:
package utility;

import java.util.Arrays;
import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Set;

public class MiscUtils {

    public static void main(String[] args) {
       Map<String, String> combos =
          findCombinations(new String[]{"chebi", "kegg.compound", "chebi"});
       System.out.println(combos.size());
       System.out.println(combos);
    }

    public static Map<String, String> findCombinations(String[] strings) {
       Set<String> set = new HashSet<String>(Arrays.asList(strings));

       if (set.size() < strings.length) {
          System.err.println("Input array contained duplicates.");
          strings = (String[])set.toArray();
       }

       Map<String, String> combos = new LinkedHashMap<String, String>();

       for (int i = 0; i < strings.length; i++)
       {
          for (int j = i + 1; j < strings.length; j++)
          {
             combos.put(strings[i], strings[j]);
          }
       }

       return combos;
    }
}

but apparently I can't handle duplicates the way I try handle them,
because I get following runtime error:
Input array contained duplicates.
Exception in thread "main" java.lang.ClassCastException:
[Ljava.lang.Object; cannot be cast to [Ljava.lang.String;
    at utility.MiscUtils.findCombinations(MiscUtils.java:23)
    at utility.MiscUtils.main(MiscUtils.java:13)

This line strings = (String[])set.toArray(); is what the runtime system
is unhappy with.

- Fencer