I want to show the warning box when I run my Java application. Just like this
How to add the certificate for showing Publisher when running my Java application?
Please show the way.
Is this your Java application, or someone elses?
If it is yours, then the primary problem is that you are using an expired certificate. You will need to go back to your certificate provider and renew it. This will most likely involve paying a new fee.
Once you got the new certificate, you will need to put it in the right place for the JAR file signer to find it. We can't tell you where that is, but your build scripts may contain some clues.
Please read the following tutorial page for general information on how to sign a JAR file:
Signing JAR Files - http://docs.oracle.com/javase/tutorial/deployment/jar/signing.html
I wanna show just like this box for my java application.
That page is displayed by the application launcher, not by the application. And if the application is properly signed, you won't see the page. The page is warning the user that something bad could be about to happen!!! (In this case, that the JAR is signed using a certificate that should no longer be trusted ... since it has expired.)
If you are not seeing a window like that and your application is not signed, it is because the launcher you are using does not require a signed JAR.
What launcher are you actually using?
I have a new certificate but I don't know how to add my certificate in the java application. I've no experience of adding certificate to the java application. Please, if you don't mind show me step by step functions.
Please read the tutorial that I linked to above.
Related
First I would like to thank this excellent site for all the help for the developers.
I am facing a problem that I need the user to browse to a specific folder on his/her machine then click the submit button.
I like to get all the filenames and types from this folder and read it in a servlet.
Idon't need upload functionality, I need to read the filenames and types in the selected folder.
Is this possible?
Thanks in advance.
The problem with reading the local file system from a web-page within the browser is the sandbox the browser runs in. Normally, you are not able to get out of that sandbox to read the local file system in such a way.
There are a few way around that, for Java you could use a signed applet, or you could use an signed ActiveX control.
Both shouldn't be that difficult, but the Java applet will have a better support all round, since the ActiveX only works on windows.
It's the signing that will become the real problem though. Is this something in a contained environment, or for the actual internet for everyone there to be able to use?
If it's a contained environment, you might be able to pull it off using a self signed certificate. Else you will need a certificate from an actual certificate authority. These can get pretty expensive.
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 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 a signed applet on a website. Because of this, the Java security dialog appears, and the user needs to grant permission to the applet before it can do it's work. What I want to do is this:
I want the website to explain the
security dialog box to the user
before it comes up. The page will
show some explanation text in a div,
and after a few seconds, the security
dialog will appear.
If the user already allowed the certificate in a previous session, it should
just run the applet without any extra
dialog.
The problem is that the security dialog appears as soon as the applet is embedded in the page. I can delay embedding, but there's no way to check it's permissions from the applet itself, since it needs to do it before it's loaded.
Perhaps I could load a second, normal applet that runs invisibly, and checks the permissions. But how would I go about doing that? Are there any Java classes that can check if a certificate has been trusted by the client?
Thanks.
You can check the certificate and signature of a JAR file programmaticly, just as the JVM would when loading the applet. It's not gonna be easy, but, at least at first glance, you're going to have to do this:
Use a hidden applet to download your JARs and verify their certificates, like the applet viewer would. You can do this manually using the java.security.cert package. The best way to figure out how to do that was the JarSigner source code, especially the verifyJar(). Something like:
// download the JAR
URL url = new URL("jar:http://mywebsite.com/myjar.jar!/");
JarURLConnection jarConnection = (JarURLConnection)url.openConnection();
// get the certificates and other security stuff
CodeSigners[] codeSigners = jarConnection.getJarEntry().getCodeSigners();
Certificate[] certificates = jarConnection.getJarEntry().getCertificates();
// verify the signatures
// don't know the code, but you can analyze JarSigner example at http://download.oracle.com/javase/tutorial/security/toolfilex/rstep2.html
Use LiveConnect (maybe something else?) to set a cookie so you know "if the user already allowed the certificate in a previous session".
Launch your applet, possibly depending on the results of (1) stores in cookies created in (2).
I haven't give this that much thought, so there might be a better way. Good luck, and post back!
I was in the process of turning my jar that reads and writes files into an applet. It displays properly until I add in the read and write function. Then Firefox just shows a black box (no error popups).
I have done a lot of research and it seems in order to get it to work I need to have the applet signed and then it will ask the user for permission, however I also read that I can't make an applet write files and it must be server side.
So my question is can I make an applet read and write files without sever side scripting?
and if so how do I get my applet signed (I read some tutorials but I'm kinda new to this).
An applet that is signed can read and write files on the local machine.
There are two types of certificates that you can use, the first is a certificate you create with keytool, an app that comes with the JDK. The second option is to sign an applet with a certificate from a Certificate Authority like Verisign.
The difference is that the self made certificate will show warning messages to the client specifying that the certificate isn't trusted. This is just a warning, but can scare users. The downside of a certificate from a real certificate authority is that it cost money.
To generate a certificate use
keytool -genkey
then to do the signing, it depends how you build your applet.
For instance if you use Ant, there is a signjar task that will sign the applet.
So my question is can I make an applet read and write files without sever side scripting?
Sure, and in a 1.6.0_10+(1) JRE (the 'Next Generation' plug-in), it does not even require the Jars to be digitally signed.
An applet deployed using Java Web Start in a next gen. plug-in has access to the JNLP API services. The FileContents object of the API provides basic I/O. Here is a demo. of using the FileContents (the source is also available at the link).
(1) Note: JWS could launch free-floating applets since Java 1.2. But with 1.6.0_10+ a JWS applet can remain embedded in a browser window (for Win. & *nix at least - I hear 'no Mac.').