We are developing java applet and embedding it in our web pages. When the applet is loaded via HTML APPLET tags, the browser/JVM prompts the user to allow it to run. When we hit cancel, the java console indicates the following exception:
java.lang.RuntimeException: java.lang.ExceptionInInitializerError
at sun.plugin2.applet.Plugin2Manager.createApplet(Unknown Source)
at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.ExceptionInInitializerError
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.newInstance0(Unknown Source)
at java.lang.Class.newInstance(Unknown Source)
at sun.plugin2.applet.Plugin2Manager$12.run(Unknown Source)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$000(Unknown Source)
at java.awt.EventQueue$1.run(Unknown Source)
at java.awt.EventQueue$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$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.lang.RuntimePermission getenv.TEMP)
at java.security.AccessControlContext.checkPermission(Unknown Source)
at java.security.AccessController.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkPermission(Unknown Source)
at java.lang.System.getenv(Unknown Source)
at downLoadApp.<clinit>(downLoadApp.java:15)
... 21 more
Exception: java.lang.RuntimeException: java.lang.ExceptionInInitializerError
Now, I realize it's most likely because the class java tried to load was prevented from loading, and therefore the exception is thrown, but how do we gracefully handle this situation in the browser? I'd like to detect that the applet was denied and post a reasonable response to the condition, but I'm unaware of how to catch this exception since it appears to have been thrown by the JVM in reaction to not getting the jar file to load rather than code written in it...
Ideas?
Thanks!
You can catch the access control exception by putting the call to System.getenv in downLoadApp.java line 15 in a try-catch statement. That is, instead of this:
static String tmp = System.getenv("TEMP");
you should have:
static String tmp;
static {
try {
tmp = System.getenv("TEMP");
} catch (java.security.AccessControlException ace) {
// tmp is not set, maybe use some default value?
}
}
Do you call System.getenv("TEMP") somewhere in the static context of the downLoadApp class? Most probably this is in the initializer of a static field, but it could be in a static code block.
This is the place where it fails (a java.security.AccessControlException is thrown). The rest of the stack trace are errors following from that. You need to catch this exception to detect that you don't have the appropriate permissions.
As you can't catch exceptions of static field initializers, you need to move the call to getenv into a method or a static code block.
I don't think that you can catch this exception as this is thrown by JVM while loading applet.
Related
Are there any smart ways to reduce logging of "equals" exceptions?
For example:
java.lang.IllegalArgumentException: Wrong parameter, should be a float from 0 to 100
at com.test.Foo.setAmount(Foo.java:93)
at com.test.Bar.setAmounts(Bar.java:39)
at com.test.Bar2.init(Bar2.java:152)
at java.awt.event.InvocationEvent.dispatch(Unknown Source) [na:1.7.0_65]
at java.awt.EventQueue.dispatchEventImpl(Unknown Source) [na:1.7.0_65]
at java.awt.EventQueue.access$200(Unknown Source) [na:1.7.0_65]
at java.awt.EventQueue$3.run(Unknown Source) [na:1.7.0_65]
at java.awt.EventQueue$3.run(Unknown Source) [na:1.7.0_65]
at java.security.AccessController.doPrivileged(Native Method) [na:1.7.0_65]
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source) [na:1.7.0_65]
at java.awt.EventQueue.dispatchEvent(Unknown Source) [na:1.7.0_65]
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source) [na:1.7.0_65]
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source) [na:1.7.0_65]
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source) [na:1.7.0_65]
at java.awt.EventDispatchThread.pumpEvents(Unknown Source) [na:1.7.0_65]
at java.awt.EventDispatchThread.pumpEvents(Unknown Source) [na:1.7.0_65]
at java.awt.EventDispatchThread.run(Unknown Source) [na:1.7.0_65]
such exception can be thrown 90 times per second under specific circumstances. We use AWT handler to log exceptions, and it can "freeze" all Swing's application.
The first workaround which came to mind was to log exceptions in a different thread, but such approch may be a real hell in later debug.
The second thought was to put exceptions in a WeakHashMap and log exception only for first occurance. Im not sure how to perform equals for exception and whether it will be fast enough at all.
If you want to use Logback, there is a Filter called DuplicateMessageFilter that drops messages after a certain repetition.
What if you write an ExceptionWrapper class and implement equals() method which compare message and stack trace. Then logger keeps LinkedHashSet of the wrappers where newly happened exceptions are added. The logger logs the Set e.g. each second (or any different time interval). Thus newly added "equal" exceptions replace older.
I am making a calculator for an AP Computer Science Final. I built the GUI in Eclipse using Jigloo, and I quickly tried to learn about Action Listeners so you can hit the buttons to make numbers appear. The problems started occurring when I started enter the actual code to make calculations. I keep getting the following error:
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at NewJFrame.<init>(NewJFrame.java:82)
at NewJFrame$1.run(NewJFrame.java:73)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$000(Unknown Source)
at java.awt.EventQueue$1.run(Unknown Source)
at java.awt.EventQueue$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
I'm pretty new to Java, and I've never attempted a project like this before. I would love if you guys can help me fix this problem. Here is a link to my actual code, it won't fit in the code box for some reason: Link to code
You button variables aren't assigned until you call initGUI(), which is at the bottom of your constructor. So, when you do this:
jButton3.addActionListener(new ListenToOne());
... Java sees this:
null.addActionListener(new ListenToOne());
... which is obviously a problem.
I am developing a simple java game and my scrollbar is raising an exception.
The scrollbar is supposed to be a "gameslider".
Exception in thread "Thread-3" java.lang.ClassCastException: sun.java2d.NullSurfaceData cannot be cast to sun.java2d.d3d.D3DSurfaceData
at sun.java2d.d3d.D3DRenderer.copyArea(Unknown Source)
at sun.java2d.d3d.D3DSurfaceData.copyArea(Unknown Source)
at sun.java2d.SunGraphics2D.doCopyArea(Unknown Source)
at sun.java2d.SunGraphics2D.copyArea(Unknown Source)
at javax.swing.BufferStrategyPaintManager.copyArea(Unknown Source)
at javax.swing.RepaintManager.copyArea(Unknown Source)
at javax.swing.JViewport.blitDoubleBuffered(Unknown Source)
at javax.swing.JViewport.windowBlitPaint(Unknown Source)
at javax.swing.JViewport.setViewPosition(Unknown Source)
at javax.swing.plaf.basic.BasicScrollPaneUI$Handler.hsbStateChanged(Unknown Source)
at javax.swing.plaf.basic.BasicScrollPaneUI$Handler.stateChanged(Unknown Source)
at javax.swing.DefaultBoundedRangeModel.fireStateChanged(Unknown Source)
at javax.swing.DefaultBoundedRangeModel.setRangeProperties(Unknown Source)
at javax.swing.DefaultBoundedRangeModel.setValue(Unknown Source)
at javax.swing.JScrollBar.setValue(Unknown Source)
at GameEnvironment.GamePanel.gameUpdate(GamePanel.java:171)
at GameEnvironment.GamePanel.run(GamePanel.java:73)
at java.lang.Thread.run(Unknown Source)
Code Line is following:
if (reachedMiddle)
scrollPane.getHorizontalScrollBar().setValue(player.getX() - (widthHorizontalScrollBar / 2));
The exception will be raised more or less randomly. I didnt figured it out so far.
I would make sure this code is run on the GUI Event Thread. If you call the Swing components on other threads you can get strange, randonm errors.
Have a look at using SwingUtilities.invokeLater(Runnable) to perform the tasks where the Swing components are updated.
I have created a jar file which throws the below error, it's a simple swing app which inserts a row when I press a button, not sure where I am going wrong please advise.
private void jButton20ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
setatmid(jTextField2.getText());
setaa10(Integer.parseInt(jTextField3.getText()));
setaa20(Integer.parseInt(jTextField4.getText()));
setaa50(Integer.parseInt(jTextField5.getText()));
setaa100(Integer.parseInt(jTextField6.getText()));
try{
System.err.println("Inserting values in Mysql database table!");
Connection con = null;
String url = "jdbc:mysql://localhost:3306/";
String db = "agents";
String driver = "com.mysql.jdbc.Driver";
Class.forName(driver);
con = DriverManager.getConnection(url+db,"root","");
Statement st = con.createStatement();
String query="INSERT INTO schedule_data (`s_ID`, `schedule_date`, `atmID`, `notification`) VALUES ('"+System.currentTimeMillis()+"','2010-09-15','"+getatmid()+"','null')";
st.executeUpdate(query);
System.err.println("1 row affected");
} catch(Exception e) {
e.printStackTrace();
}
}
Error:
java.lang.IllegalStateException: zip file closed
at java.util.zip.ZipFile.ensureOpen(Unknown Source)
at java.util.zip.ZipFile.getEntry(Unknown Source)
at java.util.jar.JarFile.getEntry(Unknown Source)
at java.util.jar.JarFile.getJarEntry(Unknown Source)
at sun.misc.URLClassPath$JarLoader.getResource(Unknown Source)
at sun.misc.URLClassPath.getResource(Unknown Source)
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 java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at atmguis.atm.jButton20ActionPerformed(atm.java:588)
at atmguis.atm.access$1600(atm.java:25)
at atmguis.atm$17.actionPerformed(atm.java:226)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(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)
The method involved is being called from the Event Dispatch Thread. I'm sure this is a part of the problem. You are trying to access the JAR file containing the com.mysql.jdbc.Driver class from this thread. This is where the error is being thrown. I have to wonder if there is some sort of concurrency issue here. Here are a couple of general notes, things that should be addressed. Once you have addressed these issues, see if you are still having a problem.
You should not be doing a database query from inside the EDT. You should collect the information you need from the swing components and then use a Runnable object to execute the SQL query on a different thread. Do a search on SO for executing code on or off the EDT to find examples of how to do this. This will ensure that your UI doesn't lock up while you wait for your SQL results.
Opening and closing a database connection every time you need one is something better left to the SQL driver and its built-in connection pooling abilities. This method should be declared on some sort of controller object which already has a reference to the SQL connection. Then, when this method is called, you call your thread as in the last step, and that thread uses the reference to the SQL connection that it already has.
This will take the line that's throwing the exception and move it out of the EDT into some sort of setup phase, presumably where you will have better luck accessing the class file. Certainly it will be a much more controlled environment than within the EDT. If there continues to be a problem accessing it, it will be easier to debug in the more controlled environment.
As an added bonus, you will also be designing your application in much more robust way.
I'm playing with things I don't really understand at the moment for a JAVA project on a Robot exploring an unknown territory (a grid of valid positions and blocked positions). Anyway, I tried to improve the basic GUI we were given as an example of how to proceed, it had been done with a text field and various unicode characters to represent the map and the robot. I tried to do it by overriding the paint method and drawing coloured rectangles to the screen to represent the map. When the program starts I'm presented with the runtime exception below but the window loads up (although for some reason the JButtons at the top are all invisible until i roll my mouse over them) and functions fine from then on.
I've got this far by trial and error and playing with examples I've found online but I guess there's something fundamental I haven't grasped here.
Thanks for any advice you can give me here.
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at Controller.paint(Controller.java:156)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.seqPaintDirtyRegions(Unknown Source)
at javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run(Unknow
n Source)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at Controller.paint(Controller.java:156)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.seqPaintDirtyRegions(Unknown Source)
at javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run(Unknow
n Source)
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)
I suggest you start by reading the Swing tutorial. It contains a section that explains how painting is done. For one thing you should be overriding the paintComponent() method. From the above error it appears your code is in the paint() method.
To learn something you should start small, then when you have problems you can post a SSCCE showing the problem.