Should You Ever Call `System.gc()`?

Calling System.gc(): A Potential Code Problem Indicator

Why is it generally frowned upon to manually invoke System.gc()?

Reasons for Caution:

1. Lack of Control: You cannot determine the specific garbage collector implementation used by the JVM, each of which may behave differently upon a System.gc() call. It may perform a full collection cycle or merely serve as a hint for the JVM.
2. Unknown Impact: In certain cases, System.gc() may even be ignored by the JVM, leading to unpredictable results.
3. Performance Issues: Stopping the world for garbage collection, if implemented, can incur performance penalties, especially during high-throughput operations.
4. Potentially Broken Code: Dependence on System.gc() for performance or correctness is typically indicative of underlying architectural flaws in the code.

Exception to the Rule:

While generally discouraged, there might be specific scenarios where using System.gc() can be considered:

1. Memory Profiling: System.gc() can help identify memory leaks by forcing the garbage collector to reclaim unused memory. This can be useful during development for debugging purposes.

Conclusion:

In most cases, it is better to rely on the JVM's automatic garbage collection mechanisms. Manual invocation of System.gc() should be approached with caution, primarily as an indicator of potential underlying code issues that need to be addressed, rather than a solution in itself.

The above is the detailed content of Should You Ever Call `System.gc()`?. For more information, please follow other related articles on the PHP Chinese website!