receiving other reference type in Java

Question

There is a parameter which is reference type, and can it receive other reference type? for instance, there is a code below

fr = new FileReader("d:\\test.txt");
br = new BufferedReader(fr);

the BufferedReader class receives FileReader type but I see in the JAVA API

BufferedReader(Reader in)

receives Reader type.

I know Reader class is abstract but it doesn't give me a clue. How is getting other types of reference as a parameter possible?

You need to understand inheritance concept of oops https://docs.oracle.com/javase/tutorial/java/IandI/subclasses.html — R. S., Nov 24 '17 at 03:19
And [this](https://docs.oracle.com/javase/8/docs/api/java/io/Reader.html) is also relevant — Nir Alfasi, Nov 24 '17 at 03:24
@alfasin do you mean if FileReader type fr is passed to Buffer reader's parameter it will be upcasted to Object class type? — meBe, Nov 24 '17 at 03:46

score 0 · Accepted Answer · answered Nov 24 '17 at 03:26

0

FileReader is a subclass of InputStreamReader, which is a subclass of Reader. That said, all public methods and variables from Reader are available in FileReader.

answered Nov 24 '17 at 03:26

Washington A. Ramos

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are you saying it is up casting? – meBe Nov 24 '17 at 03:42

receiving other reference type in Java

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