I downloaded from Internet (topcoder.com) a Java applet. When I try to open it, it says "Application blocked for security reasons" because "The certificate has expired".

Java Application Blocked dialog

I really want to launch it... So, is there a way to open and use it?

I tried to go to the Java settings and add the link to the applet to the white list, but it does not work.

  • Have you got the latest java update from Apple?
    – mmmmmm
    Jul 4, 2016 at 10:35
  • Yep, I think so.
    – Colas
    Jul 4, 2016 at 10:59

1 Answer 1


Just to be clear, the reason you are getting this error isn't because of a problem with Java on your Mac. The problem is with a certificate that has been used to sign one or more of the JAR files that make up the TopCoder Java application.

The certificate expired on March 25th this year.

Certificate details for expired certficate

If you still want to run the application, even though the certificate has expired, then you need to add it to the Exception Site List within Java Control Panel.

You may want to update Java on your Mac first though. You can get the latest download from Oracle here, Apple don't supply their own Java runtime anymore.

Security tab of Java Control Panel

  1. Launch Java Control Panel from System Preferences
  2. Select the Security tab
  3. Click on "Edit Site List..."
  4. Click on "Add"
  5. Enter "http://www.topcoder.com" in the Location field
  6. Click OK
  7. Click Apply

Now when you try to open the JNLP file you'll get a different message. Just check the "I accept the risk and want to run this application" and click Run.

Do you want to run this application? Security Warning dialog

At which point the application should successfully download and run.

TopCoder application

  • What tool did you use to display the jar certification details?
    – Mehdi
    Nov 22, 2018 at 15:46

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