Java List merge two element

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class Main {
  public static void main(String[] args) {
    List<String> lang = Arrays.asList(new String[] { "CSS", "HTML",
        "C++", "Java" });
    System.out.println(lang); /*from   w  w w  .j a  v  a 2 s. co  m*/
    System.out.println(lang.size());
    
    lang = merge(lang, 1);
    
    System.out.println(lang);
    System.out.println(lang.size());

  }

  public static List<String> merge(final List<String> list, final int index) {
    if (list.isEmpty()) {
      throw new IndexOutOfBoundsException("Cannot merge empty list");
    } else if (index + 1 >= list.size()) {
      throw new IndexOutOfBoundsException("Cannot merge last element");
    } else {
      final List<String> result = new ArrayList<String>(list);
      result.set(index, list.get(index) +" "+ list.get(index + 1));
      result.remove(index + 1);
      return result;
    }
  }

}