Which of the following statements are true?

a$.$

Some of the methods in the Collection interface cannot be implemented in the concrete subclass. In this case, the method would throw java.lang.UnsupportedOperationException, a subclass of RuntimeException.

b$.$

The AbstractCollection class is a convenience class that provides partial implementation for the Collection interface.

c$.$

The Collection interface provides the basic operations for adding and removing elements in a collection.

d$.$

The Collection interface is the root interface for manipulating a collection of objects.

e$.$

All interfaces and classes in the Collections framework are declared using generic type since JDK $1\mathrm{.}5.$