1. Startup tomcat 9.0.27 using AdoptOpenJDK\jdk-11.0.6.10-hotspot
2. Deploy war
3. Reload war
4. Trigger Perform GC in Visual VM

Output of findleaks

The following web applications were stopped (reloaded, undeployed), but their
classes from previous runs are still loaded in memory, thus causing a memory
leak (use a profiler to confirm):
/spring-boot-starter

4. Take memory dump: spring-boot-starter-reload.hprof
5. Load dump in Eclipse Memory Analyzer

Eclipse memory analyzer:

1. List objexts with incoming references and filter to **org.apache.catalina.loader.ParallelWebappClassLoader**
   1. 5 found, expecting 4: the reloaded spring-boot-starter.war, the host-manager, manager and ROOT
2. One of the classloaders has a state of DESTROYED
3. For destroyed classloaded:
   1. Path to GC roots > Excluce all phatom/weak/soft/etc references

A logback shutodwn hook appears to remain?

Repeat steps from above

Tomcat find leaks output:

The following web applications were stopped (reloaded, undeployed), but their
classes from previous runs are still loaded in memory, thus causing a memory
leak (use a profiler to confirm):
/spring-boot-complete-log4j2

EMA is similar story to with logback but the appears to be a Log4J2LoggingSystem shutdown hook this time.