need help with java nested exception.

I have created client-server gui calendar application in eclipse but it doesn't work. I have such a strange exception.. Can someone help me to solve it. As a server I used mysql and fat jar plugin for eclipse to make runnable jar file.

com.mysql.jdbc.CommunicationsException: Communications link failure due
to underlying exception:

** BEGIN NESTED EXCEPTION **

java.net.ConnectException
MESSAGE: Connection refused

STACKTRACE:

java.net.ConnectException: Connection refused
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl .java:351)
at java.net.PlainSocketImpl.connectToAddress(PlainSoc ketImpl.java:213)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.j ava:200)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.j ava:366)
at java.net.Socket.connect(Socket.java:529)
at java.net.Socket.connect(Socket.java:478)
at java.net.Socket.<init>(Socket.java:375)
at java.net.Socket.<init>(Socket.java:218)
at
com.mysql.jdbc.StandardSocketFactory.connect(Stand ardSocketFactory.java:256)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:271)
at com.mysql.jdbc.Connection.createNewIO(Connection.j ava:2771)
at com.mysql.jdbc.Connection.<init>(Connection.java:1 555)
at
com.mysql.jdbc.NonRegisteringDriver.connect(NonReg isteringDriver.java:285)
at java.sql.DriverManager.getConnection(DriverManager .java:582)
at java.sql.DriverManager.getConnection(DriverManager .java:185)
at
calendarapplication.gui.CalendarApplication.main(C alendarApplication.java:40)


** END NESTED EXCEPTION **



Last packet sent to the server was 2 ms ago.
at com.mysql.jdbc.Connection.createNewIO(Connection.j ava:2847)
at com.mysql.jdbc.Connection.<init>(Connection.java:1 555)
at
com.mysql.jdbc.NonRegisteringDriver.connect(NonReg isteringDriver.java:285)
at java.sql.DriverManager.getConnection(DriverManager .java:582)
at java.sql.DriverManager.getConnection(DriverManager .java:185)
at
calendarapplication.gui.CalendarApplication.main(C alendarApplication.java:40)
Exception in thread "main" java.lang.NullPointerException
at
calendarapplication.gui.CalendarApplication.main(C alendarApplication.java:63)


Regards,

It appears that the server is not allowing the client to connect. This could be because the port is wrong, or the network is not configured properly, or a firewall won't allo w the connection through, or no server is configured at all.

MySQL also needs to be configured to accept connections from whatever machine you are making them from.

But I am using default settings url - localhost, port - 3306, user - root, no password. What do you mean Tolls? How to do it? What I should change?

MySQL (IIRC) needs external (that includes localhost) access to be configured for a user.
Depending on your setup you might need to open up MySQL for <username>@localhost as well as <username>@127.0.0.1.

As to how exactly you'll have to refer to the MySQL documentation for you version, but this is the 5.5 doc.