We tried looking for the support matrix from Broadcom support for the latest supported OpenJDK for Access Gateway but could not find it so please direct us to where we can find this information.
Release : 12.8
Component : SITEMINDER -WEB AGENT FOR APACHE
Please see page 8 of the product support matrix:
2.4 Java Virtual Machine (JVM)
Access Gateway AdoptOpenJDK 1.8.212 (or later updates on 1.8.x) 64 bit