When installing Apigee Private Cloud patch 4.15.0.04.03 the UI component will not start unless Java 7 is being used.
This is an oversight, and should get fixed shortly.
In the meantime, if you need to use the patch, and are not using java 7 already please upgrade following the instructions to upgrade posted here:
https://community.apigee.com/articles/1704/how-to-upgrade-my-apigee-edge-opdk-from-java-6-to.html
Setup SSL for Apigee Developer Portal: Private Cloud
Qpid installation fails due qpid-proton dependency in Edge OnPrem 4.18.01
Set the expiration time for links in Private Cloud activation emails
OPDK Support for TLSv1.1 and TLSv1.2
Private Cloud (OPDK) 16.x TLS cipher support on routers and MPs
Newly added users are not able to reset their passwords using Apigee Private Cloud
Strategy to Configure SSL with Offline On-premises Edge
4.16.01/4.16.05 Edge Private Cloud doc updates for June 30
all-status.sh reports incorrect status of slapd after system reboot
How to integrate an On-Premise Edge installation with strict SMTP servers