Problem with getConnection() after exporting project to a jar file

[Ivan Bosnjak]

Hi!

My problem is this: I wrote a small test program that works with jdbc, using Microsoft SQL Server 2000 and Eclipse. The program is very similar to the test code on this page: http://support.microsoft.com/kb/313100 and everything works fine in Eclipse but after exporting the project to a jar file it won't run properly. The problem seems to be with the connection in this part of the code:

private java.sql.Connection getConnection() {
try {
Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
con = java.sql.DriverManager.getConnection(getConnectionUrl(),
userName, password);
if (con != null) {
System.out.println("Connection successful!");
String message = "Success getConnection()";
JOptionPane.showMessageDialog(DatabaseToTable.this, message, "Success",2);
}
 
} catch (Exception e) {
e.printStackTrace();
System.out.println("Error Trace in getConnection():"+ e.getMessage());
String message = e.getMessage();
JOptionPane.showMessageDialog(DatabaseToTable.this, message, "Error", 2);
}
return con;
}

To establish a connection with the database I added these external archives to my project: mssqlserver.jar, msutil.jar and msbase.jar.

Thanks for your help!

Cheers

[ September 25, 2007: Message edited by: Ivan Bosnjak ]
[ September 25, 2007: Message edited by: Ivan Bosnjak ]

[Tarun Yadav]

What's the exception that you get? Could you post the stack trace?

[Ivan Bosnjak]

Originally posted by Tarun Yadav:
What's the exception that you get? Could you post the stack trace?

After running the jar file I get the message: com.microsoft.jdbc.sqlserver.SQLerverDriver

I added the claspath variable and it still doesn't work, I also registered the driver in a way explained on the mentioned link...

Driver d = (Driver)Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver").newInstance();

I still don't understnd what's wrong

[Paul Sturrock]

After running the jar file I get the message: com.microsoft.jdbc.sqlserver.SQLerverDriver

There will be more to that message. What else does it contain? Could you post the stack trace?

[Ivan Bosnjak]

Originally posted by Paul Sturrock:

There will be more to that message. What else does it contain? Could you post the stack trace?

Ok, just to be sure you understand what I'm saying I'll repeat myself: the program works like a charm in Eclipse and no error are displayed in the console, but nothing happened when I exported and ran the jar file so I added the part of the code where the program catches the exception and displays an error message:

} catch (Exception e) {
e.printStackTrace();
String message = e.toString();
JOptionPane.showMessageDialog(DatabaseToTable.this, message, "Error", 2);
}

This option pane shows this message: java.lang.ClassNotFoundException:com.microsoft.jdbc.sqlserver.SQLServerDriver

I don't know how to export the stack trace to a file to give you a full description of the error...

[Ivan Bosnjak]

This is the full error message, I manged to export it to a file.

java.lang.ClassNotFoundException: com.microsoft.jdbc.sqlserver.SQLServerDriver
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClassInternal(Unknown Source)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at DatabaseToTable.getConnection(DatabaseToTable.java:61)
at DatabaseToTable.<init>(DatabaseToTable.java:187)
at DatabaseToTable.createAndShowGUI(DatabaseToTable.java:279)
at DatabaseToTable.access$0(DatabaseToTable.java:272)
at DatabaseToTable$1.run(DatabaseToTable.java:293)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)

[Tarun Yadav]

You should be able to see the stack trace in your console window if you run the JAR from the command line instead.

Also, you could try exploding the JAR and checking if your drivers are included in it or not.

[Paul Sturrock]

java.lang.ClassNotFoundException:com.microsoft.jdbc.sqlserver.SQLServerDriver

So you don't have the Microsoft JDBC driver in your application's classpath. Make sure you have the driver jar files in your classpath and it should work fine.

[Ivan Bosnjak]

Originally posted by Paul Sturrock:

So you don't have the Microsoft JDBC driver in your application's classpath. Make sure you have the driver jar files in your classpath and it should work fine.

I set the classpath (Win XP) in Start/Control Panel/System/Advanced/Environment Variables/ as system variables and user variables in this way:

.;c:\program files\Microsoft SQL Server 2000 Driver for JDBC\lib\msbase.jar;c:\program files\Microsoft SQL Server 2000 Driver for JDBC\lib\msutil.jar;c:\program files\Microsoft SQL Server 2000 Driver for JDBC\lib\mssqlserver.jar

Still doesn't work...

[Ivan Bosnjak]

Originally posted by Ivan Bosnjak:

Still doesn't work...[/QB]

...and it works now

I copied the three files (msbase.jar, mssqlserver.jar and msutil.jar) in a folder C:\Program Files\Java\jre1.6.0_02\lib\ext

Does that mean my program won't work if I install a new version of jre?

Thanks for the help

[Paul Sturrock]

I copied the three files (msbase.jar, mssqlserver.jar and msutil.jar) in a folder C:\Program Files\Java\jre1.6.0_02\lib\ext

Well, that is a bit of a "brute force" approach to fixing classpath issues. The problem remains that your application's classpath is not right, however you have side-stepped this problem by including the driver in your JRE. So it does mean if you change you JRE your applciation is broken again. Have a read of this - learning about the classpath and how to set it will make your life easier in the future.