The Applications Manager product jar files are signed with a Java code signing certificate that is renewed every two years. The previous certificate's validity period ended on June 8th 2017. The current certificate's validity period ends June 8, 2019.
What happens if my Java certificates are expired?
If using a release of Java 7 update 51 or later, Java will not allow Applications Manager to launch with an expired certificate.
A future release of Applications Manager version 9 will include new Java certificates with updated validity period.
Applications Manager version 8 has been out of support since March, 2018 so it will not be not be receiving a renewal to it's Java Certificates.