What does 'unsupportedoperationexception' mean in java?
This runtime exception is thrown when a method is invoked which isn't supported by the object instance or in the current context. It's often seen with unmodifiable collections.
Example:
List list = Collections.unmodifiableList(new ArrayList<>());
list.add("test");
Solution:
List modifiableList = new ArrayList<>();
modifiableList.add("test");
Always make sure you're using the appropriate type of collection or understand the limitations of the one you're working with.