If you know the size beforehand you can create an array and fill each cell directly:
String[] wikiNameArray = new String[size];
for (int i = 0; i < size; i++) {
wikiNameArray[i] = getWikiName();
}
If you don't know the size use a List
and convert it when it contains all strings
List<String> list = new ArrayList<String>();
for (Wiki wiki : wikis) {
list.add(wiki.getWikiName());
}
String[] wikiNameArray= list.toArray(new String[list.size()]);