I have a java applet project whichs starts a webcam and displays it on a window. I am trying to integrate this applet into my web-app, for that I have exported my applet as a JAR and included in my web-app and used it on my JSP page by using applet tag. Now I got a message that the digital signature cannot be verified. I am currently trying to sign my applet and use it, but I don't find any tutorials for that.
Can somebody please guide me that?
What I am trying to do is legal or can I try some other way to integrate my applet into JSP page or any other way to have webcam capture functionality in Java web application.
You need to sign an applet jar before running it as an applet. This is a link for your reff.:
http://docs.oracle.com/javase/tutorial/deployment/jar/signing.html
Once jar is signed you can run it, if it still does not work try options for running signed content under: control Panel: Java
Emm... I do suppose so when you 'exported' your applet to JAR the signature became invalid or something; actually any modifications make it invalid... so I guess you need to
A) As a tip, first clean your JRE certificates cache (then try to restart your JSP;
if it won't do then read B,C points)
B) Pack your (with blank manifest) applet into JAR
C) If you have the keystore sign the applet JAR with jarsigner util
Report if that helped
Related
I've coded a game in Eclipse (still working on it), is it possible to run it's jar file in browser so that anyone can play right from their browsers instead of downloading jar file?
I.e I upload it on my website so that anyone can play right from the link I provide them.
Consider using Java Web Start with JNLP. You can host a JNLP file on a web server somewhere, along with your jar, and users can use a desktop shortcut pointing to the link, or a browser to open your app. (Using a browser will require having a web page with an applet tag: the article mentions how to do this but doesn't separate the two.)
I'm using the following link to access JNLP API's:
Using Filechooser
The project: JWSFileChooserDemo
Basically I want an Open and Save dialog box to get "text" file from user, saving it on server, reading it, processing etc and then showing the same .java file on Website.
For the above 2 lines I've tried:
1. "Integration of Applet with Web Application", this integration works correctly but integration of "Applet .jar file in Web Application" restricts the reading of file.
2. Then I used Servlets to do the same job, but file reading doesn't works therefor me.
3. Now, I'm using JNLP, Java Web Start for the same.
But according to what I've read on the website, the applet should be signed for these file operations. Under NetbeansIDE there is an option to enable WEB START and self-signing an applet. But this doesn't work for me.
I created the same program as mentioned in the link(using javax.jnlp), but after clicking on Open, it is looping towards else statement which shows "User cancelled save request.".
I think, the above error is due applet is not signed properly as when I run the JNLP file given on the link..it asks for following confirmation i.e.
So, should I sign an applet using Project properties->WebStart->Enable WebStart->signing->self-signing by generated key or by signing it using keytools which generated certificate i.e .crt file. Is there any other way to do this?
Is there any other way to do this?
It is possible to use the JNLP API services in an unsigned application. Having said that, Oracle has decided that in a future JRE, unsigned code will not be loaded at all (using the default security preferences).
Note that those two linked pages refer to two different ways to load files.
'Using Filechooser' uses the JFileChooser provided with Swing. An applet/JWS app. that uses a file chooser needs to declare all-permissions in the launch file.
The JWSFileChooserDemo demo. OTOH, uses the JNLP API file services, and would produce a prompt at run-time similar to the one shown. At the moment these do not need to be signed.
As far as 'self signed' goes, Oracle has also put warnings against using that. The publisher of a self-signed app. at the moment, will show as UNKNOWN with extra warnings about accepting code from unknown sources. In the future, the JRE will also automatically reject self-signed code.
For the longer term, the only real option is to supply a digitally signed app. Signed using a verified certificate from a Certification Authority.
I am currently writing a Java applet (actually JApplet) that uses the Java AWS SDK to download a few files from my S3 bucket. The Applet works very well when I run it on the Applet Viewer in Eclipse, but I run into problems when I try running it on a browser.
I have indeed read a few SO questions on similar issues, but after following the answers provided, I still haven't found a solution to this problem.
At first I tried exporting a runnable jar with all dependencies included, at least for testing. But I got this error message in every browser that I tested in (Firefox, Chrome and IE):
access denied ("java.util.propertyPermission" "com.amazonaws.sdk.disableCertChecking" "read")
After some searching I found that this could be because my jar was not signed. So I self-signed it and tried again only to get the same error. I even decided to work with separate jars instead of packing them into a single jar and sign them all, to no avail.
The AwsCredentials.properties file is current and resides in the same directory as the jars, though I don't think that is what is causing the problem.
The code in HTML that I am using to embed the applet:
<applet code="path.to.class.Packer"
archive="signed-packer.jar"
width="400px" height="200px">
</applet>
Let me know if you'd like more information.
I'd appreciate any help on this issue. Thank you.
Yup. An applet running in a browser sandbox is not allowed to read arbitrary Java system properties. It is a security restriction. Signing the applet JAR file should be sufficient, provided that Java accepts the signing certificate. (Have you added your self-signed certificate to your Java installation's keystore?)
Related question: Self-signed applet doesn't get a full permission
I know similar questions have been asked but i have searched for hours and as of yet have not come up with a workable solution.
I have a Java applet which will be a "paint" like application. So, I need the user to be able to upload images from their file system. I first tried using a JFileChooser which works great in the eclipse environment. However, when put online i get a "java.security.AccessControlException: access denied" exception.
I was thinking that perhaps within the applet i could call a script (located on my server) which would prompt the user to select a file - but i have no idea how to do this. I am using zymic web hosting, so the only supported scripting language is PHP.
I also tried signing the applet. Since i don't want to spend money on certificates, i self signed the applet. When i tried running it, I got an error stating "The Publisher Cannot Be Verified By A Trusted Source".
Any help would be greatly appreciated. - Thanks:)
A trusted applet can most certainly load files from the local file-system. The "Publisher Cannot Be Verified By A Trusted Source" message that is produced by self-signed applets is onerous & scary (for good reason), but if the user OKs it, it works just fine.
Here is a small demo. of exactly that.
Since the 'Next Generation' Plug-In, even sand-boxed applets can access the local file system. See the last 2 links on the Applet tag info page for further details.
Here is an applet that uses the Next Generation file abilities.
Unsigned applets can not access the file system for security reasons.
There is a tutorial about uploading files using PHP here
Maybe you can work that into your page in order to allow the file to be uploaded and then load it from your web server with the applet.
Do keep in mind the warning at the end of that example under the section "php - file upload: safe practices"
I have an application where javascript code is accessing java applet methods that write on local disk (just to note - this is not directly possibly, but there is a workaround for it that enables to do so). Applet is self-signed applet, so users have to allow it to run first.
If applet's codebase is set to "http://..." everything works fine, in FF, Chrome and Opera as well. However, I would like to put this applet on local file system. However, if I use codebase "file://..." (I also tried to not use codebase at all and write directly full jar path to archive) it does not work, applet does not load with Warning-Security pop-up that enable user to allow running the applets.
I only tested it in FF (3.6.1.4) so far, Java version is 1.6.0.21.
Are signed applets limited only for HTTP use? Or is there some workaround?
..is there some workaround?
Perhaps using the JNLP API services in an unsigned applet will work better. I have a demo. of the JNLP FileContents object.
For details on using the JNLP services in an embedded applet see the links to the 'next generation plug-in' in the applet information page.
Applets loaded from the local filesystem are allowed to write files only in, or below, the directory containing the applet. So, if the applet is in C:\MyProjects\MyAppletTest it will be able to read and write files in that directory and its subdirectories, but not in C:\MyProjects. You can override this behavior with a policy files as explained in Quick Tour of Controlling Applets