I am unable to add an element to a list? UnsupportedOperationException

java list object add abstract
Gray Adams picture Gray Adams · Apr 8, 2012 · Viewed 13.8k times · Source

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.

Answer

John Farrelly picture John Farrelly · Apr 8, 2012

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(",")));

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