BasicFileAttributes---can interfaces be instantialized?

Question

Hi,
I have a question regarding the "BasicFileAttributes".
It is an interface? Or is there any class with the same name? As I know interface can not be instantialized, but I find this line from the sample code provided in java tutorials:
"BasicFileAttributes attr = Attributes.readBasicFileAttributes(file);"
anyone can help me to solve this problem for me? thanks

Answer 1

Tian123 wrote:
Thank you very much for your reply. I think I misunderstood the definition of instantiation. But what is the point of this line:
Foo foo = new Bar();what effect does it have on "foo"? The variable foo is declared to hold a reference to an instance of Foo. If Foo is a class, then an instance of any subclass of Foo is also an instance of Foo. If Foo is an interface, then an instance of any class the implements the interface is also an instance of Foo.
The point is coding to the interface. You should be able to google that phrase for details, but the basic idea is that you don't care what the actual implementation is, only what the type is.
One example is JDBC. In the java.sql package, Connection, Statement, RestultSet, and a whole bunch of others are interfaces. When we do Connection con = DriverManager.getConnection(...); we don't know or care what implementation class will be provided by the vendor, or even what vendor will be supplying it--Oracle, MySQL, etc.
Another example is this:
List list = new ArrayList();By declaring it as List instead of ArrayList, I'm saying that when I use the list variable, I don't care which implementation it is, as long as it meets List's contract. Later, if I decide that a LinkedList is more appropriate, I only have to change new ArrayList() to new LinkedList(). Nothing that uses the list variable needs to know or care.
>
And in these three lines:
Path file = ...;
BasicFileAttributes attr = Attributes.readBasicFileAttributes(file);
TimeUnit resolution = attr.resolution();First, the return type of the function is readBasicFileAttributes(file). what is the point to return a interface type?Same as above: You only care about the type (what the object can do), not the implementation (how it does it).