import java.io.*;public class CheckedOutputStream extends FilterOutputStream {    private Checksum cksum;    public CheckedOutputStream(OutputStream out, Checksum cksum) {        super(out);        this.cksum = cksum;    }    public void write(int b) throws IOException {        out.write(b);        cksum.update(b);    }    public void write(byte[] b) throws IOException {        out.write(b, 0, b.length);        cksum.update(b, 0, b.length);    }    public void write(byte[] b, int off, int len) throws IOException {        out.write(b, off, len);        cksum.update(b, off, len);    }    public Checksum getChecksum() {        return cksum;    }}