If you notice in general GC garbage Collector runs automatically. Since this action is automatic, there is no need to make manual calls like System.gc(). GC is a background action that runs quietly and waits for the right moment to clean up. You know, JVM is actually smarter than humans and decides on a proper time to clean up memory. Still in a few rare cases like performance testing or if you think a large amount of memory could be reclaimed, in these scenarios you can suggest garbage collection  to perform System.gc() which will be helpful. Based on the JVM's function and depending on the cases, JVM may ignore it if it does not align with the step. Also suppose if you over use this System.gc(), this can actually hurt the application's performance. If you want any solutions to address explicit System.gc() calls https://blog.gceasy.io/system-gc/, you can use the,  -XX:+DisableExplicitGC JVM argument to forcefully disable it. In the case of RMI you can control the frequencies of calls.