Issue

Getting error while opening up jnlp file in Oracle VM Manager. As a result unable to see the status of the VM's that were started.

Investigation done

1. Latest Java blocks jnlp file possibly because of its certificates related settings. At the time of writing this post the latest Java was at Version 8 with Update 181.

2. Latest Firefox blocks older java files. At the time of writing this post the latest Firefox was at Version 61.

I believe the reason for blocking is old jnlp certificate that poses a potential security risk in Java.

Resolution

This may not be the perfect solution but it works. You may try it at your own risk:

A. Downgrade Java

1. Go and find older Java SE JRE Version 7 with Update 51 from Oracle website. Download and install it,

2. Now go to your computer Control Panel > Programs > Java. Open Java program by double clicking it. 

2.1 Then go to General tab > Temporary Internet Files > Settings > Delete Files

2.2. Then go to Security tab > Security Level > downgrade the security level to "Medium"

2.3 Then go to Advanced tab > Make sure "Use TLS 1.0" is checked, and others "Use TLS 1.1" and "Use TLS 1.2" are unchecked.

2.4. Now simply hit the "OK" button at the bottom of the window to exit the Java program.

B. Downgrade Firefox

3. Uninstall the presently installed firefox.

4. Find older version of Firefox and download version 4.0 for Windows32, Language "en-US".

6. Install Firefox 4.0

C. Launch Console of VM from VM Manager

6. Now open Oracle VM Manager console > go to the VM that you started previously > and hit "Launch Console". It will download the jnlp file > then open this downloaded file > this time it will ask you to "accept the risk and launch the application" in a dialog box. Click the checkbox and hit the "Run" button.

7. This time it will simply open the console and you will be able to see the previously started VM from Oracle VM Manager.

Environment

+ Oracle VM Manager 3.2.1

+ Oracle Linux 5.x

+ Java 8 Update 181

+ Mozilla Firefox Version 61