Greetings Eclipse Gwt Project - jdbc connection problems java.lang.ExceptionInInitializerError

[biggi]

Hello everybody,

Long story short is like this: I started to develop a Gwt-Ext
application in Eclipse as a Dynamic Web Project (the tutorial that I
have followed gave me this start). Then I added Hibernate to do the
persistence and some business logic. Every thing went smooth till I
tried to deploy the app to Tomcat. This proved to be a pain in the ass
because the project wasn't a Gwt project so the war arhive was not
constructed well. I needed to do some ant work to deploy correctly the
app. Opposed to this I got the aternative to make a blank (not so
blank Greeting) project and add the sources, libs etc that I had in
the first project. Smooth again, no compiler erros, libs putted in lib
folder and added in Java build path and also in war\WEB-INF\lib\. The
problem is that when I try to execute
sessionFactory = new AnnotationConfiguration().configure
().buildSessionFactory();
I get java.lang.ExceptionInInitializerError at
com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:
284).

Not knowing what went wrong even after hours of googleing I decided to
isolate the problem. So I created a new Gwt project. Eclipse created
for me standar packages and default sources (GreetingService stuff).
Then I copied in lib folder (created by me) the mysql connector, add
also to Java build path, add 3 lines to GreetingServiceImpl:
Class.forName("com.mysql.jdbc.Driver");
String url = "jdbc:mysql://localhost:3306/mercury";
Connection con = DriverManager.getConnection(url,"root", "root");
No comilation error but at runtime when I try to execute this piese of
code the same ExceptionInInitializerError occurs.

I mention that there are no database conectivity problems (the error
is the same even if the server is closed so it doesn't even get to the
actual connecting) and I have also made a simple Java project with a
main function that connects with the same connnector in the same
fashion with no problems at all.

To be more clear I have archived the project and uploaded here:
http://rapidshare.de/files/48409199/ttt.zip.html
The full stack trace is bellow:

The server is running at http://localhost:8080/
Sep 24, 2009 10:46:49 AM
com.google.appengine.tools.development.ApiProxyLocalImpl log
SEVERE: [1253789209422000] javax.servlet.ServletContext log: Exception
while dispatching incoming RPC call
com.google.gwt.user.server.rpc.UnexpectedException: Service method
'public abstract java.lang.String
ro.mercury.client.GreetingService.greetServer(java.lang.String)' threw
an unexpected exception: java.lang.ExceptionInInitializerError
at com.google.gwt.user.server.rpc.RPC.encodeResponseForFailure
(RPC.java:360)
at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse
(RPC.java:546)
at com.google.gwt.user.server.rpc.RemoteServiceServlet.processCall
(RemoteServiceServlet.java:166)
at com.google.gwt.user.server.rpc.RemoteServiceServlet.doPost
(RemoteServiceServlet.java:86)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:713)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:806)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:
487)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter
(ServletHandler.java:1093)
at
com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter
(TransactionCleanupFilter.java:43)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter
(ServletHandler.java:1084)
at com.google.appengine.tools.development.StaticFileFilter.doFilter
(StaticFileFilter.java:124)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter
(ServletHandler.java:1084)
at org.mortbay.jetty.servlet.ServletHandler.handle
(ServletHandler.java:360)
at org.mortbay.jetty.security.SecurityHandler.handle
(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle
(SessionHandler.java:181)
at org.mortbay.jetty.handler.ContextHandler.handle
(ContextHandler.java:712)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:
405)
at com.google.apphosting.utils.jetty.DevAppEngineWebAppContext.handle
(DevAppEngineWebAppContext.java:54)
at org.mortbay.jetty.handler.HandlerWrapper.handle
(HandlerWrapper.java:139)
at com.google.appengine.tools.development.JettyContainerService
$ApiProxyHandler.handle(JettyContainerService.java:313)
at org.mortbay.jetty.handler.HandlerWrapper.handle
(HandlerWrapper.java:139)
at org.mortbay.jetty.Server.handle(Server.java:313)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:
506)
at org.mortbay.jetty.HttpConnection$RequestHandler.content
(HttpConnection.java:844)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:644)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:205)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:381)
at org.mortbay.io.nio.SelectChannelEndPoint.run
(SelectChannelEndPoint.java:396)
at org.mortbay.thread.BoundedThreadPool$PoolThread.run
(BoundedThreadPool.java:442)
Caused by: java.lang.ExceptionInInitializerError
at com.mysql.jdbc.NonRegisteringDriver.connect
(NonRegisteringDriver.java:284)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at ro.mercury.server.GreetingServiceImpl.greetServer
(GreetingServiceImpl.java:23)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse
(RPC.java:527)
... 27 more
Caused by: java.security.AccessControlException: access denied
(java.lang.RuntimePermission modifyThreadGroup)
at java.security.AccessControlContext.checkPermission(Unknown Source)
at java.security.AccessController.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkPermission(Unknown Source)
at com.google.appengine.tools.development.DevAppServerFactory
$CustomSecurityManager.checkPermission(DevAppServerFactory.java:128)
at com.google.appengine.tools.development.DevAppServerFactory
$CustomSecurityManager.checkAccess(DevAppServerFactory.java:155)
at java.lang.ThreadGroup.checkAccess(Unknown Source)
at java.lang.Thread.init(Unknown Source)
at java.lang.Thread.<init>(Unknown Source)
at java.util.TimerThread.<init>(Unknown Source)
at java.util.Timer.<init>(Unknown Source)
at java.util.Timer.<init>(Unknown Source)
at com.mysql.jdbc.ConnectionImpl.<clinit>(ConnectionImpl.java:258)
... 36 more


Can anyone help me... any ideeas on how to connect on server side to a
data base in a Gwt app?

Thank you in advance. I'm waiting your answer.

Truly,
Stefan Voinea

[Isaac Truett]

Stefan,

Are you aware that you have your project configured to use Google App
Engine? App Engine will not let you open a socket to a database.

http://code.google.com/appengine/docs/java/runtime.html#The_Sandbox

- Isaac