There are multiple cases when UnsupportedOperationException can happen. Usually it happens when List implementation haven’t realized this method. For example, if we will try to use the following specialList String[] specialArray = {"str1"}; List specialList = Arrays.asList(specialArray); to add new element: specialList.add("str2"); it will throw exception with the following stacktrace: Exception in thread "main" java.lang.UnsupportedOperationException […]