Run local java applet in browser (chrome/firefox) "Your security settings have blocked a local application from running"

Question

I'm trying to run a Java Applet (html file), but the browser keeps saying:

"Your security settings have blocked a local application from running"

I have tried using Chrome and Firefox but i get the same error. I have upgraded to the latest version of Java, but Chrome still says in

chrome://plugins/ "Download Critical Security Update"

even though i can run Java applets (not locally)

Im using Ubuntu 13.04 64 bit

Crucial

Answer 1

After reading Java 7 Update 21 Security Improvements in Detail mention..

With the introduced changes it is most likely that no end-user is able to run your application when they are either self-signed or unsigned.

..I was wondering how this would go for loose class files - the 'simplest' applets of all.

Local file system

Your security settings have blocked a local application from running

That is the dialog seen for an applet consisting of loose class files being loaded off the local file system when the JRE is set to the default 'High' security setting.

---

Note that a slight quirk of the JRE only produced that on point 3 of.

1. Load the applet page to see a broken applet symbol that leads to an empty console.
   Open the Java settings and set the level to Medium.
   Close browser & Java settings.
2. Load the applet page to see the applet.
   Open the Java settings and set the level to High.
   Close browser & Java settings.
3. Load the applet page to see a broken applet symbol & the above dialog.

Internet

If you load the simple applet (loose class file) seen at this resizable applet demo off the internet - which boasts an applet element of:

<applet
    code="PlafChanger.class"
    codebase="."
    alt="Pluggable Look'n'Feel Changer appears here if Java is enabled"
    width='100%'
    height='250'>
<p>Pluggable Look'n'Feel Changer appears here in a Java capable browser.</p>
</applet>

It also seems to load successfully. Implying that:-

Applets loaded from the local file system are now subject to a stricter security sandbox than those loaded from the internet or a local server.

Security settings descriptions

As of Java 7 update 51.

• Very High: Most secure setting - Only Java applications identified by a non-expired certificate from a trusted authority will be allowed to run.
• High (minimum recommended): Java applications identified by a certificate from a trusted authority will be allowed to run.
• Medium - All Java applications will be allowed to run after presenting a security prompt.

Buccal

Thnx for your answer @Andrew I think ill take a look on Appleteer :) seems it will work – Crucial

Answer 2

Go to java control tab>java control pannel>click security tab>down the security level to medium. Then applet progrramme after 2to 3 security promt it will run.

Lapith

Yes, this worked for me. I had to shut everything down and made sure in the task manager that chrome & java were dead. Then I restarted and everything worked fine. Thank you!. – Eratosthenes

Or you add the given site in the list of authorized websites – Reeve

There is no longer a "Medium" option on OS X. :/ – Misconduct

Answer 3

For XP: Start > Control Panel > Java > Security > (Set to Medium) http://www.java.com/en/download/help/java_update.xml

Landgrave

This worked for development purposes, however it's a bad idea due to the security risk involved. – Peroneus

If you have another solution just share with us. – Landgrave

Unfortunately I haven't been able to find another way to make it work, so I upvoted your answer. – Peroneus

Unfortunately Java 8 for Linux only has "High" and "Very High" security settings. It is already in its lowest ("high" ¯\_(ツ)_/¯) – Gasp

Answer 4

In my case, this has been resolved by going to control panel > java > security > then add url in the exception site list. Then apply. Test again the site and it should now allow you to run the local java.

Mesonephros

Answer 5

I think the upgrade of Java will not help. You need to uninstall the old version and then install the latest java version to help you. Make sure that you restart the computer once you are done with the installation.

Hope it helps!

Mayda

Thanks for your answer @Juned Ahsan :) But I have tried that and it doesn't work either. I can run java applets (like visting javatester.org), but I cant run my own applets locally. Think ill uninstall JDK 7, restart pc, and install 7 again. Ill update if it works or not – Crucial

Answer 6

This problem happens when older versions of java still on your system disrupt any new versions installed. To stop this problem you need to first remove all java software using - Control Panel + Remove Programs + then uninstall java. (At this stage, I recommend cleaning out your registry using CCleaner using their Registry option or similar program to ensure a clean sweep then reboot) After rebooting reinstall the most recent version of java and all will be well.

http://www.filehippo.com/download_ccleaner -LINK TO CCLEANER

Rhombohedron

Sadly CCLEANER isn't available for Ubuntu – Crucial

This problem is not related to having more than one Java on a machine; it's to do with Java's security settings on recent version. – Plessor

Answer 7

just add your .jar file in applet tag as an attribute as shown below:

<applet
    code="file.class"
    archive="file.jar"
    height=550 
    width=1100>         
</applet>

Dolerite

Answer 8

1. Make a jar file from your applet class and META-INF/MANIFEST.MF file.
2. Sign your jar file with your certificate.
3. Configure your local site permissions as > file:///C:/ or http: //localhost:8080
4. Then run your html document on Intenet Explorer on Windows.(Not Google Chrome !)

Wellread