MYSQL 's fault?

[disappearedng]

Hi everyone,
I am currently using mysql 5.16 jdk 1.6 and Mysql-connector-java 5.16 to do some database stuff.

I have written the following code:

DisplayAuthor.java

[disappearedng@miuky1 ~/Desktop]$ cat DisplayAuthors.java
import java.sql.*;
import java.util.Properties;

public class DisplayAuthors     {

        static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
        static final String DATABASE_URL = "jdbc:mysql://localhost/books";

        /**
         * @param args
         */
        public static void main(String[] args)  {

                Connection connection = null;
                Statement statement = null; 

                try {
                        Class.forName( JDBC_DRIVER ); //load database driver class

                        connection = DriverManager.getConnection( DATABASE_URL, "disappearedng", "secret");
                        statement = connection.createStatement();

                        ResultSet resultSet = statement.executeQuery(
                                        "SELECT authorID, firstName, lastName FROM authors");

                        ResultSetMetaData metaData = resultSet.getMetaData();
                        System.out.println( metaData.toString());

                        int numberOfColumns = metaData.getColumnCount();
                        System.out.println( "Authors Table of Books Database: ");

                        for (int i = 1; i <= numberOfColumns; i++ )
                                System.out.printf("%-8s\t", metaData.getColumnName(i) );
                        System.out.println();

                        /*
                        resultSet.next();
                        for (int i = 1; i <= numberOfColumns; i++) 
                                System.out.printf("%-8s\t", resultSet.getObject( i ) );
                        */

                        while ( resultSet.next() )      { //next returns true iff it can position to the next role
                                for (int i = 1; i <= numberOfColumns; i++) 
                                        System.out.printf("%-8s\t", resultSet.getObject( i ) );
                                System.out.println()    ;
                        }
                }

                catch ( SQLException sqlException )             {
                        System.out.println("SQL EXCEPTION!!!!!!!!!!!!");
                        sqlException.printStackTrace();
                        System.exit( 1);
                }
                catch ( ClassNotFoundException classNotFound )  {
                        System.out.println("CLASS NOT FOUND ERROR !!!! ");
                        classNotFound.printStackTrace();
                        System.exit( 1 );
                }

                finally         {

                        try             {
                                statement.close();
                                connection.close();
                        }

                        catch (Exception exception)     {
                                exception.printStackTrace();
                        }

                }

        }
}

and this is my classpath

[disappearedng@miuky1 ~/Desktop]$ echo $CLASSPATH
/home/disappearedng//Dev/MySQL-Connector-java/mysql-connector-java-5.1.6/mysql-connector-java-5.1.6-bin.jar:.:/home/disappearedng/Dev/XML_Parser/xerces-2_9_1/*.jar

and this is the error produced when I run the compiled class:

[disappearedng@miuky1 ~/Desktop]$ java DisplayAuthors 
SQL EXCEPTION!!!!!!!!!!!!
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

Last packet sent to the server was 0 ms ago.
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
        at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
        at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1074)
        at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2103)
        at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:718)
        at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:46)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
        at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
        at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:302)
        at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:282)
        at java.sql.DriverManager.getConnection(DriverManager.java:582)
        at java.sql.DriverManager.getConnection(DriverManager.java:185)
        at DisplayAuthors.main(DisplayAuthors.java:20)
Caused by: java.net.ConnectException: Connection refused
        at java.net.PlainSocketImpl.socketConnect(Native Method)
        at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)
        at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)
        at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)
        at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
        at java.net.Socket.connect(Socket.java:519)
        at java.net.Socket.connect(Socket.java:469)
        at java.net.Socket.<init>(Socket.java:366)
        at java.net.Socket.<init>(Socket.java:209)
        at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:253)
        at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:280)
        at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2026)
        ... 12 more

Note that I Have SQLexception to print something so I know there is something definitely faulty with the mysql database or the way my class is compiled.

and just to let you guys see if my database is running well,
here is my db.err file:

[disappearedng@miuky1 ~/Desktop]$ sudo cat /var/db/mysql/miuky1.no-domain-set.bellcanada.err 
Password:
081014 00:11:36 mysqld_safe Starting mysqld daemon with databases from /var/db/mysql
081014  0:11:38  InnoDB: Started; log sequence number 0 83383
081014  0:11:38 [Note] Event Scheduler: Loaded 0 events
081014  0:11:38 [Note] /usr/local/libexec/mysqld: ready for connections.
Version: '5.1.22-rc'  socket: '/tmp/mysql.sock'  port: 3306  FreeBSD port: mysql-server-5.1.22
081014  0:19:46 [Note] /usr/local/libexec/mysqld: Normal shutdown

081014  0:19:46 [Note] Event Scheduler: Purging the queue. 0 events
081014  0:19:46  InnoDB: Starting shutdown...
081014  0:19:49  InnoDB: Shutdown completed; log sequence number 0 83383
081014  0:19:49 [Note] /usr/local/libexec/mysqld: Shutdown complete

081014 00:19:49 mysqld_safe mysqld from pid file /var/db/mysql/miuky1.no-domain-set.bellcanada.pid ended
081014 00:20:57 mysqld_safe Starting mysqld daemon with databases from /var/db/mysql
081014  0:20:59  InnoDB: Started; log sequence number 0 83383
081014  0:20:59 [Note] Event Scheduler: Loaded 0 events
081014  0:20:59 [Note] /usr/local/libexec/mysqld: ready for connections.
Version: '5.1.22-rc'  socket: '/tmp/mysql.sock'  port: 3306  FreeBSD port: mysql-server-5.1.22

BTW I am running on freebsd 7.0 and this is my my.conf

[disappearedng@miuky1 ~/Desktop]$ cat /etc/my.conf 
[client]
port=3306
[mysqld]
skip-bdb
port            =       3306
bind-address    =       127.0.0.1
skip-name-resolve
safe-show-database

What the hell is wrong?

[TerryP]

Oddly, you don't mention anything about your network.


It might just have been my time spent shouting WTH are these exceptions from when using Rubies Net::* classes under Win32 with a restrictive firewall; but I would be inclined to believe either your system is refusing the connection or mysqld is spiting on you.


Out of curiosity, what happens when you try to connect via a mysql client?

$ mysql -u youruser -h yourdbhost -p yourdb
   ...

Does the user/db combo you have set in your program have the necessary access rights? As my Grandfather would probably say... If the lamp won't turn on, check if it's unplugged before you throw out the lightbulb.

[disappearedng]

Originally Posted by TerryP

Oddly, you don't mention anything about your network.


It might just have been my time spent shouting WTH are these exceptions from when using Rubies Net::* classes under Win32 with a restrictive firewall; but I would be inclined to believe either your system is refusing the connection or mysqld is spiting on you.

Why though? How would I be able to check if my system is actually refusing the connection?

Originally Posted by TerryP

Out of curiosity, what happens when you try to connect via a mysql client?

$ mysql -u youruser -h yourdbhost -p yourdb
   ...

[disappearedng@miuky1 /usr/home/disappearedng]$ mysql -u disappearedng -h localhost -p books
Enter password: 
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.1.22-rc FreeBSD port: mysql-server-5.1.22

Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

mysql>

Originally Posted by TerryP

Does the user/db combo you have set in your program have the necessary access rights? As my Grandfather would probably say... If the lamp won't turn on, check if it's unplugged before you throw out the lightbulb.

I would like to check that. I have even ran as root to access my java class file so I don't know whether that's the issue.

[TerryP]

I'm not a smart man when it comes to this stuff here (most people here are much so my superiors in knowledge).


But the way I do such testing, is generally via telnet for TCP based and via custom program/script for UDP based communication.


telnet myhost my_protocols_port

e..g tcp$ telnet foob 6789 or udp$ myscript.ext foob 6789 and see if I get a connection refused or actually get a reply of some sort.


Maybe someone here knows a nicer way.