Develop Reference

Additional Permission required if Java Console is open?

I've found an interesting behaviour in my Java Applet.
All seems to work fine, but when i have the Java Console Window the Applet does nothing and i can see the following exception to be thrown in the Java Console:
Exception in thread "Thread-33" java.security.AccessControlException: access denied ("java.lang.RuntimePermission" "accessClassInPackage.com.sun.deploy.uitoolkit.impl.awt.ui")
at java.security.AccessControlContext.checkPermission(Unknown Source)
at java.security.AccessController.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkPackageAccess(Unknown Source)
at sun.plugin2.applet.SecurityManagerHelper.checkPackageAccessHelper(Unknown Source)
(...)
So my question is now, why does the Application need more permissions when the console is open than when its closed? I've tried to google the permission but no one seems to have had any problems with this.

Java Applet with Mysql ExceptionInInitializerError

I'm using java applet with mysql connection. I used Netbeans to build paths. When my applet works in localhost, I got an error.
Exception in thread "Abandoned connection cleanup thread" java.security.AccessControlException: access denied ("java.lang.RuntimePermission" "setContextClassLoader")
at java.security.AccessControlContext.checkPermission(Unknown Source)
at java.security.AccessController.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkPermission(Unknown Source)
at sun.plugin2.applet.AWTAppletSecurityManager.checkPermission(Unknown Source)
at java.lang.Thread.setContextClassLoader(Unknown Source)
at com.mysql.jdbc.AbandonedConnectionCleanupThread.run(AbandonedConnectionCleanupThread.java:38)
I just use mysql-applet Netbeans. Can you help me ?

If you upgrade your MySQL Connector/J to 5.1.26 this should be fixed. Previously there was a call to 'setContextClassLoader()' which was removed for other reasons. See http://bugs.mysql.com/bug.php?id=68556

applet with swing mysql and a config file works in eclipse but fails in browser

Hi it's probably because i'm a noob, but i'm trying to get this working for days now so hope that someone can help me....
The idea:
For a java training i need to make a Java applet that reads and writes data from a (localhost) MySQL database. The settings from this database have to come out of a config.ini file.
The application runs fine as an applet and a java application in Eclipse.
It also runs fine as an executable jar file.
I can't get it running as an applet though...:(.
The first error that i got was about reading the config.ini file. I expect that this happens because of the security limitations (io). It is something that needs to be solved but not my main concern for now.
In order to see if the rest works i skip my loadIni class. Then i got a: driver not found exception.
I solved this by loading the mySQL jar as an archive in my applet ().
But now i'm lost...
When i start the applet in the browser i get the following error in the console:
java.lang.RuntimeException: java.lang.ExceptionInInitializerError
at com.sun.deploy.uitoolkit.impl.awt.AWTAppletAdapter.instantiateApplet(Unknown Source)
at sun.plugin2.applet.Plugin2Manager.initAppletAdapter(Unknown Source)
at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.ExceptionInInitializerError
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:327)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at Kreta.DBConnection.<init>(DBConnection.java:39)
at Kreta.AfhaalMenus.<init>(AfhaalMenus.java:21)
at Kreta.test2.<init>(test2.java:39)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at java.lang.Class.newInstance(Unknown Source)
at com.sun.deploy.uitoolkit.impl.awt.AWTAppletAdapter$1.run(Unknown Source)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$200(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(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)
Caused by: java.security.AccessControlException: access denied ("java.util.PropertyPermission"
"file.encoding" "read")
at java.security.AccessControlContext.checkPermission(Unknown Source)
at java.security.AccessController.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkPermission(Unknown Source)
at sun.plugin2.applet.AWTAppletSecurityManager.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkPropertyAccess(Unknown Source)
at java.lang.System.getProperty(Unknown Source)
at com.mysql.jdbc.StringUtils.<clinit>(StringUtils.java:70)
... 31 more
I really hope that somebody can send me in the right direction.

Applets are not allowed to do a number of things, including file I/O and various networking tasks; as your applet is trying to do one. You may need to sign you applet.
Check this reference
http://www.coderanch.com/how-to/java/HowCanAnAppletReadFilesOnTheLocalFileSystem

The answer is signing all jars.
how to do this was still a quest but the following post made it really easy:
how do i sign a java applet

An applet should not have direct access to the DB. This is for the security of the DB. Instead it should be forced to go through a web service that (limits what the user can do &) itself interacts with the DB.
An applet communicating with a DB (or a web service) on the same host that served it can be sand-boxed.
If that 'reading properties' error is part of the DB connection code you do not control, that is a good case for hiding the DB access behind the web service. Otherwise there are ways of reading a properties file (from the originating server) that do not invoke an AccessControlException.
Having said all that, it is getting to the stage where unsigned code is likely to be blocked before it is ever loaded, so perhaps the first thing you should do is digitally sign the applet and all required libraries.
Why code an applet? If it is due to spec. by teacher, please refer them to Why CS teachers should stop teaching Java applets. This will be easier to do with a standard desktop app. launched using Java Web Start. The security environment will be the same, but a free-floating app. is:
A better experience for the end user.
A lot easier to code and maintain than an applet embedded in a web page.

Jena + Pellet + Slick in an applet

I am trying to integrate Jena libs, Pellet and some RPG 2d library Slick all together in an applet.
So basically when I run the applet in the browser I get this file permission error (the jars I am using are all signed):
Exception in thread "Thread-15" java.lang.ExceptionInInitializerError
at org.mindswap.pellet.ABox.<init>(ABox.java:208)
at org.mindswap.pellet.KnowledgeBase.clear(KnowledgeBase.java:540)
at org.mindswap.pellet.KnowledgeBase.<init>(KnowledgeBase.java:418)
at org.mindswap.pellet.jena.PelletInfGraph.<init>(PelletInfGraph.java:99)
at org.mindswap.pellet.jena.PelletReasoner.bind(PelletReasoner.java:95)
at org.mindswap.pellet.jena.PelletReasoner.bind(PelletReasoner.java:53)
at com.hp.hpl.jena.ontology.impl.OntModelImpl.generateGraph(OntModelImpl.java:2744)
at com.hp.hpl.jena.ontology.impl.OntModelImpl.<init>(OntModelImpl.java:139)
at com.hp.hpl.jena.ontology.impl.OntModelImpl.<init>(OntModelImpl.java:128)
at com.hp.hpl.jena.rdf.model.ModelFactory.createOntologyModel(ModelFactory.java:410)
at RPGGame.GameSelectionScreen.init(GameSelectionScreen.java:170)
at RPGGame.RPGGame.initStatesList(RPGGame.java:39)
at org.newdawn.slick.state.StateBasedGame.init(StateBasedGame.java:164)
at org.newdawn.slick.AppletGameContainer$Container.initApplet(AppletGameContainer.java:272)
at org.newdawn.slick.AppletGameContainer$ContainerPanel.initGL(AppletGameContainer.java:229)
at org.newdawn.slick.AppletGameContainer$ContainerPanel.start(AppletGameContainer.java:216)
at org.newdawn.slick.AppletGameContainer$1.run(AppletGameContainer.java:92)
Caused by: java.security.AccessControlException: access denied ("java.util.PropertyPermission" "pellet.configuration" "read")
at java.security.AccessControlContext.checkPermission(Unknown Source)
at java.security.AccessController.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkPropertyAccess(Unknown Source)
at java.lang.System.getProperty(Unknown Source)
at org.mindswap.pellet.PelletOptions.<clinit>(PelletOptions.java:805)
Thanks in advance,
Ioana

The error is because ABox is trying to read information out of PelletOptions, which needs to load the Pellet configuration. It will usually try to read this out of the jar, but first, it double checks if the user specified in the system properties a different location than the default. It's this check that is causing the error.
You can just modify PelletOptions to always check in the jar and avoid the system properties check, or you might be able to twiddle the applet security stuff to make this ok (I don't know if that's possible, never used an Applet before).

"access denied" when using JDBC from a browser applet

I have a java applet that queries an Oracle database for data. When run from inside an IDE, it functions just fine. But when I run it as an applet embedded in a webpage, I get an "access denied" error in the class loader, and I haven't the foggiest notion what it is requiring of me:
Sep 06, 2011 12:58:48 PM oracle.jdbc.driver.OracleDriver registerMBeans
WARNING: Error while registering Oracle JDBC Diagnosability MBean.
java.security.AccessControlException: access denied ("java.lang.RuntimePermission" "getClassLoader")
at java.security.AccessControlContext.checkPermission(Unknown Source)
at java.security.AccessController.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkPermission(Unknown Source)
at java.lang.Thread.getContextClassLoader(Unknown Source)
at oracle.jdbc.driver.ClassRef.<init>(ClassRef.java:75)
at oracle.jdbc.driver.ClassRef.newInstance(ClassRef.java:51)
at oracle.jdbc.driver.OracleDriver.registerMBeans(OracleDriver.java:311)
at oracle.jdbc.driver.OracleDriver$1.run(OracleDriver.java:199)
at java.security.AccessController.doPrivileged(Native Method)
at oracle.jdbc.driver.OracleDriver.<clinit>(OracleDriver.java:195)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at com.binderton.oracle.ConnectionManager.open(ConnectionManager.java:17)
at com.sun.javafx.applet.FXApplet2$2.run(Unknown Source)
at com.sun.javafx.application.PlatformImpl$3.run(Unknown Source)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.access$100(Unknown Source)
at com.sun.glass.ui.win.WinApplication$1$1.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
java.lang.ExceptionInInitializerError
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at com.binderton.oracle.ConnectionManager.open(ConnectionManager.java:17)
at com.sun.javafx.applet.FXApplet2$2.run(Unknown Source)
at com.sun.javafx.application.PlatformImpl$3.run(Unknown Source)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.access$100(Unknown Source)
at com.sun.glass.ui.win.WinApplication$1$1.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: java.security.AccessControlException: access denied ("java.lang.RuntimePermission" getClassLoader")
at java.security.AccessControlContext.checkPermission(Unknown Source)
at java.security.AccessController.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkPermission(Unknown Source)
at java.lang.Thread.getContextClassLoader(Unknown Source)
at oracle.jdbc.driver.ClassRef.<init>(ClassRef.java:75)
at oracle.jdbc.driver.ClassRef.newInstance(ClassRef.java:51)
at oracle.jdbc.driver.OracleDriver.<clinit>(OracleDriver.java:260)
... 12 more
Got ErrorEvent[url=null label=Failed to start application. cause=null

Applets runs in an environment with very restrictive security rules. You need at least to sign your applet.
But, the problem is bigger here, doing JDBC inside an applet is a very bad idea. The applet's source code is publicitly available and is thus sensitive for easy hacks. You should really create a webservice for that instead and then let your applet access that webservice instead. With a webservice, your applet will be able to exchange information with the DB by just HTTP requests/responses. With a webservice you hide the DB access details, JDBC and SQL code from the public.
How exactly to create a webservice depends on the server environment and the programming language used. In Java EE for example, you could already use a simple Servlet for this, but also JAX-RS and JAX-WS is supported for restful (XML/JSON) and XML webservices respectively. An applet is without any security restrictions allowed to connect with its host whose address is available by getCodeBase() E.g.
InputStream response = new URL(getCodeBase(), "servlet?foo=bar").openStream();
// ...

Note that if you follow the advice of BalusC and hide the DB behind a an active page (e.g. a servlet, PHP, ASP etc.) that is on the same server as the applet, the applet could most probably remain sand-boxed. It would be the active page that is trying to access class-loaders (as well as the DB).