When you stop the SAS Web Application Server, many messages can appear in the log that indicate likely or probable memory leaks similar to the following:

ERROR | [WebappClassLoader] | The web application [/SASxxxxx] created a ThreadLocal with key of type [java.lang.InheritableThreadLocal] (value [java.lang.InheritableThreadLocal@1c6b4c1a]) and a value of type [com.sas.framework.commons.TenantIdentifier] (value [TenantIdentifier [id=-1, moniker=Server]]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak. 
ERROR | [WebappClassLoader] | The web application [/SASxxxxxxxx] appears to have started a thread named [xxxx.xxx.xxx Thread] but has failed to stop it. This is very likely to create a memory leak.

These messages are expected behavior, and you can ignore them.