Non Static Variable addressed to Static Variable

Question

Hi,
I am new to java, I am getting (Non Static Variable sb,serverAddress addressed to Static Variable)
Here is the code. Thanks for reading, any help or explanation would be appreciated-
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package webcheck;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.ProtocolException;
import java.net.URL;
* @author
public class checkhttp {
      private URL serverAddress = null;
      private StringBuilder sb = null;
      public checkhttp(java.net.URL serverAddress,java.lang.StringBuilder StringBuilder)
          this.serverAddress=serverAddress;
          this.sb=sb;
  public static void main(String[] args) {
      HttpURLConnection connection = null;
      OutputStreamWriter wr = null;
      BufferedReader rd  = null;
      String line = null;
      int x;
      //checkhttp check= new checkhttp();
      try {
          serverAddress = new URL("http://www.yahoo.com");
          //set up out communications stuff
          connection = null;
          //Set up the initial connection
          connection = (HttpURLConnection)serverAddress.openConnection();
          connection.setRequestMethod("GET");
          connection.setDoOutput(true);
          connection.setReadTimeout(10000);
          connection.connect();
          //get the output stream writer and write the output to the server
          //wr = new OutputStreamWriter(connection.getOutputStream());
          //wr.write("");
          //wr.flush();
          //read the result from the server
          rd  = new BufferedReader(new InputStreamReader(connection.getInputStream()));
          sb = new StringBuilder();
          while ((line = rd.readLine()) != null)
              sb.append(line + '\n');
          System.out.println(sb.toString());
          System.out.println("Server is up");
      } catch (MalformedURLException e) {
          e.printStackTrace();
      } catch (ProtocolException e) {
          e.printStackTrace();
      } catch (IOException e) {
          e.printStackTrace();
      finally
          //close the connection, set all objects to null
          connection.disconnect();
          //rd = null;
          //sb = null;
          //wr = null;
          connection = null;
}

Answer 1

Someone please correct me if I'm wrong, but since main is static, any fields it access must also be static.
The static keyword declares that something is accessable no matter the class state, thus you can call main() and run your program without having something make an instance of the object that your progam defines. For example:
class Foo {
      static public String strText = "Hello World";
//Later in some method, this is valid.
String MyString = Foo.strText;
//However, if strText was not static you need to
Foo fooExample = new Foo();
String myString = fooExample.strText;Static should not override private, so static private fields/members are not accessable. To be accessable you still need to be public.
Edited by: porpoisepower on Jan 21, 2010 2:18 PM