Exception "The connection attempt failed." (didn't find anything elsewhere)

Hello,

  I'm quite new at java and I was just following a tutorial when I bumped
with a horrible exception. The program compiled smoothly, but when I runned
it I got an error message and I wasn't able to found any track through the
internet. So I would like to know if any of you could help me. Here is the
error track spilled from my VM:

org.postgresql.util.PSQLException: The connection attempt failed.
org.postgresql.util.PSQLException: The connection attempt failed.
        at
org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:136)
        at
org.postgresql.core.ConnectionFactory.openConnection(ConnectionFactory.java:65)
        at
org.postgresql.jdbc2.AbstractJdbc2Connection.<init>(AbstractJdbc2Connection.java:117)
        at
org.postgresql.jdbc3.AbstractJdbc3Connection.<init>(AbstractJdbc3Connection.java:30)
        at
org.postgresql.jdbc3.Jdbc3Connection.<init>(Jdbc3Connection.java:24)
        at org.postgresql.Driver.connect(Driver.java:235)
        at java.sql.DriverManager.getConnection(DriverManager.java:512)
        at java.sql.DriverManager.getConnection(DriverManager.java:171)
        at HelloPostgresql.<init>(HelloPostgresql.java:34)
        at HelloPostgresql.main(HelloPostgresql.java:118)
Caused by: java.net.UnknownHostException: localhost
        at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:153)
        at java.net.Socket.connect(Socket.java:452)
        at java.net.Socket.connect(Socket.java:402)
        at java.net.Socket.<init>(Socket.java:309)
        at java.net.Socket.<init>(Socket.java:124)
        at org.postgresql.core.PGStream.<init>(PGStream.java:58)
        at
org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:77)
        ... 9 more

A little note: I think that attempt to connect wasn't completed because it
didn't generate any entry in the postgresql log files.

Here's the code I compiled...

/**
* A demo program to show how jdbc works with postgresql
* Nick Fankhauser 10/25/01
* nickf@ontko.com or nick@fankhausers.com
* This program may be freely copied and modified
* Please keep this header intact on unmodified versions
* The rest of the documentation that came with this demo program
* may be found at http://www.fankhausers.com/postgresql/jdbc
*/


import java.sql.*;   // All we need for JDBC
import java.text.*;
import java.io.*;

public class HelloPostgresql
{
  Connection       db;        // A connection to the database
  Statement        sql;       // Our statement to run queries with
  DatabaseMetaData dbmd;      // This is basically info the driver delivers
                              // about the DB it just connected to. I use
                              // it to get the DB version to confirm the
                              // connection in this example.

  //CONSTRUCTOR
  public HelloPostgresql(String argv[]) throws ClassNotFoundException,
SQLException
  {
    String database = argv[0];
    String username = argv[1];
    String password = argv[2];

    Class.forName("org.postgresql.Driver"); //load the driver

    db = DriverManager.getConnection("jdbc:postgresql:"+database,
                                     username,
                                     password); //connect to the db

    dbmd = db.getMetaData(); //get MetaData to confirm connection

    System.out.println("Connection to "+dbmd.getDatabaseProductName()+" "+
                       dbmd.getDatabaseProductVersion()+" successful.\n");

    sql = db.createStatement(); //create a statement that we can use later


    String sqlText = "create table jdbc_demo (code int, text varchar(20))";
    System.out.println("Executing this command: "+sqlText+"\n");
    sql.executeUpdate(sqlText);


    sqlText = "insert into jdbc_demo values (1,'One')";
    System.out.println("Executing this command: "+sqlText+"\n");
    sql.executeUpdate(sqlText);


    sqlText = "insert into jdbc_demo values (3,'Four')";
    System.out.println("Executing this command twice: "+sqlText+"\n");
    sql.executeUpdate(sqlText);
    sql.executeUpdate(sqlText);


    sqlText = "update jdbc_demo set text = 'Three' where code = 3";
    System.out.println("Executing this command: "+sqlText+"\n");
    sql.executeUpdate(sqlText);
    System.out.println (sql.getUpdateCount()+
                        " rows were update by this statement\n");


    System.out.println("\n\nNow demostrating a prepared statement...");
    sqlText = "insert into jdbc_demo values (?,?)";
    System.out.println("The Statement looks like this: "+sqlText+"\n");
    System.out.println("Looping three times filling in the fields...\n");
    PreparedStatement ps = db.prepareStatement(sqlText);
    for (int i=10;i<13;i++)
    {
      System.out.println(i+"...\n");
      ps.setInt(1,i);         //set column one (code) to i
      ps.setString(2,"HiHo"); //Column two gets a string
      ps.executeUpdate();
    }
    ps.close();


    System.out.println("Now executing the command: "+
                       "select * from jdbc_demo");
    ResultSet results = sql.executeQuery("select * from jdbc_demo");
    if (results != null)
    {
      while (results.next())
      {
        System.out.println("code = "+results.getInt("code")+
                           "; text = "+results.getString(2)+"\n");
      }
    }
    results.close();


    sqlText = "drop table jdbc_demo";
    System.out.println("Executing this command: "+sqlText+"\n");
    sql.executeUpdate(sqlText);


    db.close();
  }

  public static void correctUsage()
  {
    System.out.println("\nIncorrect number of arguments.\nUsage:\n "+
                       "java   \n");
    System.exit(1);
  }

  public static void main (String args[])
  {
    if (args.length != 3) correctUsage();
    try
    {
      HelloPostgresql demo = new HelloPostgresql(args);
    }
    catch (Exception ex)
    {
      System.out.println("***Exception:\n"+ex);
      ex.printStackTrace();
    }
  }
}

Thanks In Advance,
Pedro

_________________________________________________________________
MSN Messenger: converse online com seus amigos .
http://messenger.msn.com.br