Ubuntu - saying your security settings have blocked an application from running with an out-of-date version of java

Question

I need to perform a load testing on our websocket service. Is there a way to open multiple websocket connections from a single workstation?

I already tried npm ws and websocketmodules to launch them with NodeJS. It works fine with a single connection, but when I try to open them in a for-loop it throws an exception or uses only last open client.

Solution

Since the last Update to jdk 7u51, in the default settings of java (High) is not allowing to run java untrusted apps. I could remember to run some apps with same high security some days ago but now those are getting blocked. Only applets having a certificate and proper permissions attribute can be run.

How to run apps without certificate

• Update your jdk, latest is available here.
• [Never recommend, Do only if you trust the app] Open Java Control Panel by running javaws -viewer, Keep your security settings to Medium, it will allow all applications to run except applications that request all permissions. So it is vulnerable, should you run a malicious application^[source]

Comments

[jmreicha]

Just to help others in the future - to open the control panel easily you can type in javaws -viewer

[Bruce]

The control panel for Oracle Java 8 now omits the 'medium' setting, but the 'high' setting combined with an exception appears to permit unsigned apps to run, albeit with a lot of security warnings (which should be heeded!).

[Petr Shypila]

Thank you! This helped me. Also npm websocket finally worked out!