I need help from java sorceries.

Question

Hello, I've discovered some magic in Java sources.
I looked into HttpURLConnection code, there is absolutely nothing about sockets. Look at this getStatusCode method:
getInputStream();
String resp = getHeaderField(0);
responseCode = parse(resp);Neither getInputStream() nor getHeaderField(int) are not defind in HttpUrlConnection class. Yes, these methods are defined in UrlConnection. Here is how it is done:
public String getHeaderField(int n) {return null;}
public InputStream getInputStream() throws IOException
{throw new UnknownServiceException("protocol doesn't support input");}Seems that UrlConnection do not support these metods. My only problem was to discover how can I read character header from binary socket stream and parse it without depricated readLine in DataInputStream.

Answer 1

HttpURLConnection is an abstract class, so it does not provide the implementation of what you're looking for. When you need an object of HttpURLConnection, you can't use new HttpURLConnection(), instead, you use URL.openConnection() or something like that. In that method, an object of the HttpURLConnection is created (actually an object of its sub-class as all abstract method must be implemented).
you should be able to get any header info via an object of HttpURLConnection, as all methods have already been implemented, though not in the HttpURLConnection class.
BTW, if you like readLine(), find it in BufferedReader class, it's the replacement of DataInputStream, but it's not recommanded for networking communication, as the new line control character(s) is platform dependant (some use '\n', while some use '\r\n').