The invocation of System.gc() or Runtime.getRuntime().gc() triggers stop-the-world Full GCs, freezing the JVM and potentially degrading user experience. These calls can originate from various sources including developers, libraries, and RMI. Detecting these calls is crucial, and enabling GC logs can help. Possible solutions include using the JVM argument '-XX:+DisableExplicitGC' or configuring RMI's gcInterval properties.