You don't, but it doesn't matter. You'll iterate them using a for loop (
for (int i = 0; i < items.length; ++i)), or use a for each syntax (
for (String d : items)). If you use the for loop (not the foreach syntax), then you can simply pull the key based on the value of i.
Since I would assume you either tokenized or used the string's split method, you can make your comparisons using the .equals() function on it. Don't compare strings with ==.
If this data comes from something stored like a database, then you should review the schema as you have a normalization problem with the property holding a collection.