UnsupportedOperationException: Thrown to indicate that a requested operation is not supported.
Example:

import java.util.Collections;
import java.util.List;
List list = Collections.unmodifiableList(new ArrayList());
try {
 list.add("Hello");
} catch (UnsupportedOperationException e) {
 System.out.println("Caught UnsupportedOperationException: " + e.getMessage());
}