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This one list object is biting me in the butt..
Any time I try to add an element to it, it produces this:
Caused by: java.lang.UnsupportedOperationException
at java.util.AbstractList.add(AbstractList.java:148)
at java.util.AbstractList.add(AbstractList.java:108)
The line producing the error is insignificant, but here it is anyways:
AdventureLobbies.players.add(args[0].toLowerCase());
Should I not be accessing it statically?
Actual declaration of variable:
AdventureLobbies.players = Arrays.asList(rs.getString("players").toLowerCase().split(","));
Any ideas? Can't find anything on Google that's worthwhile.
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The UnsupportedOperationException can be resolved by using a mutable collection, such as ArrayList , which can be modified. An unmodifiable collection or data structure should not be attempted to be modified.
There are two methods to add elements to the list. add(E e): appends the element at the end of the list. Since List supports Generics, the type of elements that can be added is determined when the list is created. add(int index, E element): inserts the element at the given index.
You insert elements (objects) into a Java List using its add() method. Here is an example of adding elements to a Java List using the add() method: List<String> listA = new ArrayList<>(); listA. add("element 1"); listA.
List in Java provides the facility to maintain the ordered collection. It contains the index-based methods to insert, update, delete and search the elements. It can have the duplicate elements also. We can also store the null elements in the list.
Arrays.asList() will give you back an unmodifiable list, and that is why your add is failing. Try creating the list with:
AdventureLobbies.players = new ArrayList(Arrays.asList(rs.getString("players").toLowerCase().split(",")));
The java docs say
asList
@SafeVarargs
public static <T> List<T> asList(T... a)
"Returns a fixed-size list backed by the specified array"
Your list is fixed size, meaning it cannot grow or shrink and so when you call add, it throws an unsupported operation exception
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