I'm trying to capture images by using webcam in an applet. The applet makes use of JMF. But I managed to run applet without actually installing JMF. I kept a button in HTML webpage so that when the button gets clicked, the applet should capture the image.
But for me it is giving a java.lang.RuntimeException: No permission to capture from applets. How can this exception be resolved so an applet can capture image using webcam in HTML page?
In order to capture images in an applet, it is necessary:
For you to digitally sign the code.
For the user to click "OK" when prompted to run the signed code.
If the functionality is being called from a button using JavaScript, wrap the Java code in one of the AccessController.doPrivileged(PrivilegedAction) variants.
AFAIR the installer for JMF does not have the 'allow capture from applets' checked by default. That needs to be reconfigured in the JMF options. I forget how.
Update
I dont want to give client package to extra overhead of the installation of JMF.
That is just silly.
The components of the JMF must be available on the run-time class-path of the applet, for it to function. If they are downloaded by the JRE using the applet element (or whatever), then the user has incurred that 'overhead'.
But perhaps you mean you don't want to make the end user run the installer that advises to 'reboot' at the end. In that case, you are missing my point while avoiding answering my question. That question, again, is "How did you get the DLL?".
Applets run with very limited permissions and that might be causing the issue.. Here is an old post which has information about signing an applet to get the necessary permissions..hope this helps
I think flash is a much better option. There are really easy solutions for that even using Javascript + Flash.
Take a look at this: http://www.xarg.org/project/jquery-webcam-plugin/
This question asked Too many times in this forum..
Anyways..Here is the solution: Java swing Program to capture webcam images
you have to modify it for applet which takes only 30 minutes
Related
I'm using IntelliJ IDEA, I have coded a frame which I want to put into an HTML file so I can run it in my browser, how do I do this now that I cannot use JApplet? I have found this documentation: http://docs.oracle.com/javase/tutorial/deployment/webstart/deploying.html and this http://docs.oracle.com/javase/tutorial/deployment/webstart/deploying.html but I am new to programming and find this difficult to follow. I don't know for instance how I would go about putting my class files and the image that I used in a separate directory nor do I know how I go about signing my application so that it will run in a browser.
I want to put into an HTML file so I can run it in my browser,
You can use the Desktop class. This class allows you to access default applications from your desktop.
Read the section from the Swing tutorial o How to Integrate With the Desktop class for more information and working examples.
See Java Plugin support deprecated and Moving to a Plugin-Free Web.
Note that is one of my 'copy/paste comments' that does not explicitly mention JFrame based apps., however the links are still relevant in that Oracle & browser makers would not be phasing out support for applets if they wanted programmers to keep trying to shove rich client apps (e.g. Swing GUIs) into thin client web pages.
OTOH you can offer a JFrame (or a JApplet) to be launched from a link in a web page to end up free floating on the desktop of the user by using Java Web Start.
Even then, it is not a simple matter for the programmer or the end user. The programmer needs to ensure the app is digitally signed using a code signing certificate issued by a CA (usually they are expensive). The end user used to just be able to click the link, 'OK' the prompts produced by the Java virtual machine, and see the app appear on-screen. But now most browsers will download the launch file to the local file system rather than directly hand it to the JVM to be launched. So the user faces an extra step in explicitly finding the downloaded launch file and double clicking it.
This is all due to security concerns related to bugs in the plug-ins that run things in web pages. So if you were to find a way around all these hoops, please let us know. It is a security bug that requires urgent fixing.
I have a javacard and it has 2 applets installed. Now I would like to select one among the two. Currently how I do is that, I provide the cap file of the applet from which I get its AID. But I don't find this method satisfactory. So
Is there a way or steps to get the AID of the applets installed in a java card without having the cap file?
Is there a way to select the applet without its AID? By this I mean that is there a way to make an applet auto selectable after reset?
Are there any other ideas or insights over this?
For the questions you have asked,
Yes. PyApduTool can make you reach you goal. This tool can help you get all the packages' or applets'AID in java card even though you don NOT have the cap file.
Just press the "Refresh" button. the things you need appears in the right text field.
You can set you applet as "Default Selected" when installing it.
In this way, you can make you applet selected by default without having to know its AID.
For convenience, it should be better to know the applet-AID.
Only one applet can be the default selected.
The answer from Andy is good but i feel that its missing an important part of the question:
Javacard get applet AID of installed applets through Java code
If the question refers to finding installedf Applets from the code of one java card applet itself than this answer might apply:
First, it is possible to get the AID of the applet itself by JCSystem.getAID().
Second, it is not possible to "detect" other applets from within an installed applet.
Although if you know the other applet's AID you can get a hack of useful information about it using JCSystem and GPSystem.
So apart from inside JavaCard code, the Card Manager is able to list of installed applets with all their privileges and so on. You can use a tool of your choice. If you are working with JCOP, I recommend JCOP Shell. If you work with freeware I recommend Global Platform Pro from Martin Paljak.
Beside selecting AIDs and default selection there is no direct way to select an applet. There is an indirect way by using the SharedObjectInterface mechanism from JavaCard which lets you change control flow to a different applet.
I have a simple java applet that retrieves an image from a server and prints it out. The only problem is that I get the following java security warning:
Researching on this site and all over the web, some people suggest that I sign the applet (I tried that to no avail) and others suggest that I Modify a local java security setting but that isn't feasible for my clients.
Not only do I get this warning at the start of my applet, but seemingly any time the code attempts to interact with the printer, the dialog re-appears. Also, note that there is no checkbox next to 'Always allow this applet to access the printer'. These symptoms show on any browser.
How do I get java to respect the users choice to allow it to send jobs to the printer?
You might use the JNLP API services in a sand-boxed applet in a plug-in 2 JRE. They will still prompt the user each first time they go to print, but should also put an 'always allow' check-box on the dialog (though it really only applies for that run). See a demo. of the PrintService.
See also the applet info. page that includes a link on the Next Generation in Applet Java Plug-in Technology which "..brings new abilities to applets: such as .. allowing embedded applets to gain full access to the services of Java Web Start."
Is it possible to take a screen shot (using the Print Screen) and paste it from the System Clipboard directly into a web pages text area field (which I would create)? Do I need a browser plug-in? Can Flash do this?
**The solution only has to work in Internet Explorer.
This is not possible without a plugin.
It's not possible in Flash or Silverlight either, although it is possible in AIR.
I think you will have to write a custom ActiveX Control in order to do this. The control should automatically take a screenshot and send captured image to server-side code..
There is one more option - create a java applet, which will do the job, and also will help you to avoid cross browser issue.
How does http://www.screentoaster.com capture a computer screen from a browser using Java Applet? Any suggestion or a lead in how to accomplish this? Is there other way to do using using different technology such as Flash?
You can do it with just 5 lines of code.
1 . Create one rectangle representing
screen. 2 . Create one BufferedImage
to store image of the screen. 3 . Take
snapshot using new
Robot().createSnapshot() method. 4 .
Save the bufferedImage in file.
Robot class is part of java.awt package
You can see more detail in the below link.
http://java.sun.com/j2se/1.4.2/docs/api/java/awt/Robot.html
I haven't tried it (I don't want to risk it!!!), but the indications are that it screen toaster uses a signed applet, and you have to explicitly accept a certificate (which gets added to your browser's trusted cert store) to enable the applet to break out of the normal Java security sandbox. (I'm also taking your word for it that it does use an applet ...)
I would hope that other methods of capturing the user's screen via a web-browser are similarly protected.
I would also like to hope that most users are not crazy enough to install random browser plugins or accept random certificates. But sadly, this is not true.
This whole idea strikes me as being very risky. What is to stop the Screen Toaster guys from taking their own copy of what is on your screen, installing a key-logger, ferreting around for sensitive files, installing a rootkit, etc? And assuming that they are entirely honest, how do you know that their applet doesn't have a security flaw that could be exploited by someone else to do the same thing?