"application blocked by security settings" prevent applets running using oracle SE 7 update 51 on firefox on Linux mint

Question

Background

Complete fresh installation of Oracle Java SDK (32-bit) on Linux. The installation is correct, the plugin is correctly installed.

Problem

The following error ("Application Blocked by Security Settings") appears when the applet runs inside Firefox:

Setup

Here are the steps I used:

1. Installed Linux mint 16 on VBox: > uname -a Linux me-VirtualBox 3.11.0-12-generic #19-Ubuntu SMP Wed Oct 9 16:12:00 UTC 2013 i686 i686 i686 GNU/Linux
2. Cleaned all Java instances.
3. Followed instructions to install jdk-7u51-linux-i586.tar.gz on Linux.
4. Verified installation > java -version java version "1.7.0_51" Java(TM) SE Runtime Environment (build 1.7.0_51-b13) Java HotSpot(TM) Client VM (build 24.51-b03, mixed mode)
5. Verified plugin: > pwd /home/me/.mozilla/plugins > ls -l total 0 lrwxrwxrwx 1 me me 46 Jan 22 02:42 libnpjp2.so -> /usr/lib/jvm/jdk1.7.0/jre/lib/i386/libnpjp2.so
6. Verified Java plugin:
7. Verified Firefox activation:
8. Started the Java ControlPanel; set security to Medium:
9. Clicked Apply.
10. Restarted Firefox.

Question

How do you change the security settings to allow the applet to run?

Answer 1

Just start your browser with superuser rights, and don't forget to set Java's JRE security to medium.

Answer 2

$pwd /usr/lib/jvm/jre1.8.0_25/bin

./jcontrol

as follow,

java Control Panel --> Security --> Edit Site list ,
then apply, and ok.

Answer 3

You can also use Edit Site List and make it be an exception so that you can run it from the specific website.

Answer 4

The application that you are running is blocked because the application does not comply with security guidelines implemented in Java 7 Update 51

Answer 5

As an alternative answer, there's a command line to invoke directly the Control Panel, which is javaws -viewer, should work for both openJDK and Oracle's JDK (thanks @Nasser for checking the availability in Oracle's JDK)

Same caution to run as the user you need to access permissions with applies.

Answer 6

I had this issue. The security settings in the ControlPanel seem to be user specific. Try running it as the user you are actually running your browser as (you are not browsing as root!??) and setting the security level to Medium there. - For me, that did it.