The CMS garbage collector is the default garbage collector that is used with Apache Cassandra. CMS is known as a generational garbage collector. It works by dividing the Java heap into contiguous ranges of memory. Each range of memory or generation is responsible for holding objects that are created (and eventually discarded) by a Java application.
When certain conditions arise, the garbage collector runs and reclaims heap space by collecting unused objects, and promoting the remaining objects (survivors) to a different generation:
Figure 4.2: A representation showing the different sections of the JVM heap when using the CMS garbage collector ...
