What should be checked for GC activity according to the predefined static thresholds?

The correct answer focuses on monitoring Garbage Collection (GC) activity by using predefined static thresholds that aim to identify when performance may be adversely affected due to excessive garbage collection.

Specifically, when GC time exceeds 40%, it is typically considered a critical threshold indicating that the application may be spending too much time in garbage collection rather than executing meaningful application code. This can lead to degraded performance or increased latency for user transactions, thus necessitating attention from the developers or system administrators.

Monitoring GC activity is important because high GC times can be symptomatic of underlying issues such as inadequate memory allocation, inefficient code, or memory leaks. By keeping a close eye on this threshold, teams can proactively address potential performance problems before they impact users.

The thresholds above 40% serve as an early warning to prevent performance issues, while lower thresholds would not necessarily capture critical degradation in user experience. This method allows teams to fine-tune application performance by addressing memory management appropriately.