inout.java

import java.io.IOException;

/**
 * Class that copies stdin to stdout, as compained about as not being cleanly
 * writable in Java on Hacker News.
 * In real code, you would just write IOUtils.copy(System.in, System.out),
 * which does basically the same thing.
 * This does not catch any exceptions as a) this is just an "exercise" and
 * b) all we could do with them is pretty-print them. So let the runtime 
 * print them for you.
 *
 * Usage: javac inout.java && echo -e "foo\nbar" | java InOut
 */
class InOut {
    public static void main(String[] args) throws IOException {
        byte[] buffer = new byte[8192];
        while(true) {
            int bytesRead = System.in.read(buffer);
            if (bytesRead == -1) {
                return;
            }
            System.out.write(buffer, 0, bytesRead);
        }
    }
}