Question

The classes java.io.Reader and java.io.InputStreamReader both have read methods with the exact same signature

public int read(char[] charbuf, int offset, int length) throws IOException

Now according to the java documentation the class java.io.FileReader inherits both these read() methods from both the above-mentioned classes.

Now as FileReader extends InputStreamReader which further extends Reader

(Reader <-- Inputstreamreader <-- FileReader)

and the read() has same signature in both classes, shouldn’t it have been that InputStreamReader overrode the read() from Reader and FileReader inherited that over-ridden method?? Or am i missing something here??

Also the two read()s inherited by FileReader have slightly different functionality (something about one blocks while waiting for input while the other doesn’t).

Answer 1

The method in InputStreamReader provides the implementation for the abstract method in Reader. FileReader doesn’t override that method any further; it just inherits the implementation from InputStreamReader.

Note that there are four signatures for read:

public int read()
public int read(char[] cbuf, int offset, int length)
public int read(char[] cbuf)
public int read(CharBuffer target)

InputStreamReader only overrides the first two of these. Perhaps that’s what was confusing you?