An object that may hold resources (such as file or socket handles)
until it is closed. The close() method of an AutoCloseable
object is called automatically when exiting a
try-with-resources block for which the object has been declared in
the resource specification header. This construction ensures prompt
release, avoiding resource exhaustion exceptions and errors that
may otherwise occur.
@apiNote
It is possible, and in fact common, for a base class to
implement AutoCloseable even though not all of its subclasses or
instances will hold releasable resources. For code that must operate
in complete generality, or when it is known that the AutoCloseable
instance requires resource release, it is recommended to use
try-with-resources constructions. However, when using facilities such as
java.util.stream.Stream that support both I/O-based and
non-I/O-based forms, try-with-resources blocks are in
general unnecessary when using non-I/O-based forms.