import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
String[] array = new String[] {"str1", "str2"};;
ArrayList<String> projection = new ArrayList<String>(Arrays.asList(array));
List<String> list = Arrays.asList(arr);
List<String> list = new ArrayList<String>();
list.add("str1");
list.add("str2");
int size = list.size();
String[] arr = (String[])list.toArray(new String[size]);