Here are some samples:
sending binary data
sending user agent
sending authentication


#1
urlConn.setRequestProperty("CONTENT-TYPE", "application/x-www-form-urlencoded"); System.out.println("Content type = " + urlConn.getRequestProperty("CONTENT- TYPE")); 
// returns "application/x-www-form-urlencoded"

out = new PrintStream(urlConn.getOutputStream());
out.print(strPostInfo);    // this does not work; content-type is blank

#2
...
connection = url.openConnection();
connection.setRequestProperty ( "User-agent", "my agent name");
connection.setRequestProperty ( "From", "my name");
stream = connection.getInputStream();
...

This compiles and runs fine except the request has been sent before I
get a chance to set the request headers!  The server side gets
"Java1.02" as the user-agent.  I've also tried:

...
import sun.net.www.protocol.http.HttpURLConnection;
...
conn = new HttpURLConnection(url);
conn.setRequestProperty ( "User-agent", "my agent name");
conn.setRequestProperty ( "From", "my name");
conn.connect();
stream = conn.getInputStream();
...

#3
import java.net.*;
import java.io.*;
import sun.misc.*;

public class Geturl {
 public static void main (String url) {
  System.out.println(Geturl(url, "", ""));
 }

 public static String encode (String source) {
  BASE64Encoder enc = new sun.misc.BASE64Encoder();
  return(enc.encode(source.getBytes()));
 }

 public static String Geturl (String URL, String Name, String Password)
{
  String thisLine;
  String retVal;
  URL u;
  URLConnection uc;
  retVal = "";
  try { u = new URL(URL);
   try {
    uc = u.openConnection();
    if (Name != null) {
     uc.setRequestProperty("Authorization", "Basic " + encode(Name + ":"
+ Password));
    }
    InputStream content = (InputStream)uc.getInputStream();
    BufferedReader in = new BufferedReader (new InputStreamReader
(content));
    String line;
    while ((line = in.readLine()) != null) {
     retVal += line;
    }
   } catch (Exception e) {
    return "";
   }
  } catch (MalformedURLException e) {
   return(URL + " is not a parseable URL");
  }
  return retVal;
 }
}