How to create a zip file with java.util.zip package

public static void createZip(String filename,String zipfilename) {
        try {
            byte[] buf = new byte[1024];
            FileInputStream fis = new FileInputStream(filename);
            fis.read(buf,0,buf.length);
            
            CRC32 crc = new CRC32();
            ZipOutputStream s = new ZipOutputStream(
                    (OutputStream)new FileOutputStream(zipfilename));
            
            s.setLevel(6);
            
            ZipEntry entry = new ZipEntry(filename);
            entry.setSize((long)buf.length);
            crc.reset();
            crc.update(buf);
            entry.setCrc( crc.getValue());
            s.putNextEntry(entry);
            s.write(buf, 0, buf.length);
            s.finish();
            s.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }