"java.io.IOException: Stream closed" with new BufferedReader

Question

Many people asked question like that but this one is a little bit different. Here is the code:

public static BufferedReader reader;    
public static String readString() throws IOException {
            reader = new BufferedReader(new InputStreamReader(System.in));
            String s = reader.readLine();
            reader.close();
            return s;
        }

While program runtime readString method is invoked many times. The second call causes exception: stream closed. I can not understand: why it ends up so? Every time we declare new BufferedReader. So the stream must be also new. Or not?

If not, how should I organize my program so that it will close reader after all invocations and after my program is over?

Akash Thakare · Accepted Answer · 2016-01-01 01:01:25Z

3

Because System.in is same Object (public final static InputStream in; of System class) both method calls are using, closing in one method will automatically close System.in for other method. You should close the BufferedReader from outside(as I can see it's public) the method once you finish calling readString and so it will ultimately close underlying System.in.

edited Jan 1, 2016 at 1:01

answered Jan 1, 2016 at 0:53

Akash Thakare

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user207421 · Accepted Answer · 2016-01-01 01:33:36Z

2

Closing the BufferedReader closes System.in. You shouldn't close it at all, and you shouldn't keep creating a new one either: you will lose data. Use the same one for the life of the process.

answered Jan 1, 2016 at 1:33

user207421

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