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
Related
I'm having a lot of difficulty getting an applet I made to run in a web browser. Java security keeps blocking it. I have the jar sitting on my desktop and I made a simple html file that embeds the jar using . I'm trying to embed this in html for my website. I don't have any root access to the site at all so I want to avoid using Web Start and Apache Tom Cat stuff because it seems those tutorials assume you're uploading the app itself to the directory of the site itself. I can only embed html here, so I have a jar located in my googledrive.com/host that I'm trying to link.
Here's the code for the tag.
<applet
codebase="https://bb2f18b1cb19b925c50b747c1c65afcc4ad11720.googledrive.com/host/0B34NA0csYJZufm5ZeFFEcUMyQnR5bmw1eVl2M3BOcXItNGxxZTZvaFExNVhXQnY4dzY3QTg"
archive="AsteroidGameApp.jar"
code="asteroidgame.AsteroidGame.class"
width=500
height=500>
</applet>
I don't even know if it would run correctly or not because I can't get past the security. I've read stuff about getting the code signed but I can't find a clear tutorial how to do that.
As reported on the Java related site Starting with Java 7 Update 51, trying to run unsigned Java applications generates error messages and prevents executing the applet.
Follow the instructions about the Oracle proper solution (I my experience I had to get a valid certificate from a trusted root like Verisign and then used this certificate to sign my applet jar) but if you can't do this way, try the suggested workaround in the correspondent section.
Obviously, as stated by the Java site:
It is highly recommended not to run these types of applications. However if you still want to run these apps, run only if you understand the risks and implications.
I've written a Java applet game that I want to deploy on my Apache server. Code + resources are in a self signed .jar with accompanying HTML doc both in the root dir. When I run it on my local machine everything works fine. When I try to run on the server I get a class not found exception. index.html contains
<applet code=SpaceRaiderz.class
archive=spaceraiderz.jar
width=1024 height=768>
</applet>
The class not found is the class named above. Opened up the .jar and its contents are complete. File permissions set to 755. If I click the index.html on my local machine it loads up and runs perfectly. Ftp the same docs to the server and it doesn't work. Anyone had this problem? I found a similar question to this on here but none of the suggested solutions have worked in this case.
The applet (seen here) works (e.g. showing an asteroids style game featuring a pale green ship that appears suspiciously familiar + sound track) for me in Java 1.7.0_21 on Windows using FF. Refreshing the class cache in the console & then refresh the page might fix the problem for you.
If that fails, there are still more options for testing the applet:
Usually installing another browser (these things are often due to a problem in the particular browser/JRE combo.).
There is also the Appleteer applet testing environment. I can highly recommend it, Since I wrote it.
Go to an internet cafe or the local library to check an applet, if all else fails.
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
I'm writing my own Java applet that can write to /tmp on my local unix machine.
this applet is only going to run on a html page, inside my machine only. No server involved.
But when I try to open my page inside Firefox, the applet doesn't seem to work at all. I don't understand why, since all the .class, .html and .jar files are on the same directory.
Need help.
A normal applet can't access the filesystem, as they are by default not trusted.
To enable filesystem access and other things (like native librarys) for an applet it has to be signed.
When a signed applet is loaded into the browser the first time, a notification pops up requesting the user to confirm that the applets signature is trusted.
More information here.
I don't know very much about applets, but I remember that one basic constraint is that they can't access the local filesystem.
If you want to do that one good option is to use Javascript. EDIT: But it will not work directly!