Java Virtual Machine Information
The first deep dive you can make is into metadata about the Java Virtual Machine. This page contains details regarding the Garbage Collector configuration being used as well as which flags are applied in the JVM.
Garbage Collection Configuration
The Garbage Collection Configuration has information about which Garbage Collector(s) are being used, and configuration for them. For OpenJDK 8 through 17, the safe bet is using the G1 collector. If this says anything else, it should be an intentional choice.
The JVM has many different flags which controls how it operates. The Flags have sane defaults, and should generally not be fiddled with. Being able to tell which flags were used may help in debugging though.