DriverManager.getConnection() : very strange behavior

Question

I am currently developping a SWING application generated with NetBeans 6.1 which connects to either a MySQL DB or a PostgresSQL DB, both hosted by a Linux server.
The application runs just FINE on Solaris/SPARC, Solaris/x86 and Linux/x86.
The problems come with Windows/x86 : the call to DriverManager.getConnection() just stalls, no error, no timeout, no exception.
After investigating a little bit more I found some "funny" behaviors that I submit here for comments:
The drivers loaded since the main() function using:
Class.forName("com.mysql.jdbc.Driver");
Class.forName("org.postgresql.Driver");
The application gets connected to the DB with the following connection code :
try {  
DriverManager.getConnection( "jdbc:mysql://192.168.2.3:3306/ZEDB", "user", "pwd" );
DriverManager.getConnection( "jdbc:postgresql://192.168.2.3:5432/ZEDB", "user", "pwd" );
catch (Exception x) {  [...] }
And the results are (tried with JDK 5u16 and JDK 6u7)
- On Windows :
-> OK in a console Application
-> OK in a Swing/AWT Application if the connection code is in the main function
-> NOK in a Swing/AWT Application if the connection code is placed anywhere within a SWING Form AND server is remote,
-> Last case if OK if server is "localhost" (tested only with MySQL -for Windows- however ).
- On Linux or Solaris : OK on any case
Any idea ?
- Dom

Answer 1

Dom- wrote:
I made at first the same assumption as you did.
But when I put the "connecting code" into the static main() function - without changing anything else - then it worked. So I can't believe that it is due to any Windows firewalling rules as the rest doesn't change when the code changes place.When it is impossible then it means your assumptions are wrong.
Hard to say what your assumptions are in this case. But some possibilities. There can be countless others.
1. You are not running the code that you think you are.
2. It is not blocking where you think it is.
And I obviously need to run that connecting code within Swing forms as it is the user who decides which DB to use and what the credentials are...
I can understand that I have a fundamental design issue. But going again through the whole wizard of Netbeans with a very basic Swing application, I step already on this misbehavior: OK from "static main()", NOK from "App.startup()".Note that myself I didn't say you had a design issue. I don't do GUIs so I certainly don't know how to do them correctly. But I do know that if you have blocking code and you are not careful then it will block the GUI and make it non-responsive to the user.