UnsupportedOperationException on Collection

Question

While studying the Collection API, we find that some methods (add, remove,...) may throw a java.lang.UnsupportedOperationException

Answer 1

Yes. For example when you call Collections.unmodifiableList(list), the returned list does not support add(..)

These collections, however, are mostly private classes which are not exposed an an API, so you cannot instantiate them.