Which statement is true about the take method defined in the WatchService interface?
A.
Retrieves and removes the next watch key, or returns null of none are present.
B.
Retrieves and removes the next watch key. If a queued key is not immediately available, the
program waits for the specified wait time.
C.
Retrieves and removes the next watch key: waits if no key is yet present.
D.
Retrieves and removes all pending events for the watch key, returning a list of the events that
were retrieved.
Explanation:
The WatchKey take() method retrieves and removes next watch key, waiting if none
are yet present.
Note: A watch service that watches registered objects for changes and events. For example a file
manager may use a watch service to monitor a directory for changes so that it can update its
display of the list of files when files are created or deleted.
A Watchable object is registered with a watch service by invoking its register method, returning a
WatchKey to represent the registration. When an event for an object is detected the key is
signalled, and if not currently signalled, it is queued to the watch service so that it can be retrieved
by consumers that invoke the poll or take methods to retrieve keys and process events. Once the
events have been processed the consumer invokes the key’s reset method to reset the key which
allows the key to be signalled and re-queued with further events.
Reference: Interface WatchService