G1 GC is an adaptive garbage collection algorithm that has become the default GC algorithm since Java 9.
The article discusses the differences between APM tools like AppDynamics and GC log analysis tools such as GCeasy. APM tools monitor application performance in production, while GCeasy offers detailed insights into Garbage Collection metrics, phases, causes, and optimization recommendations. GCeasy complements APM tools, enhancing memory management and performance tuning across environments.
Users may want to analyze specific time intervals within GC logs instead of the entire log. Common scenarios include analyzing logs from the last 24 hours or during high traffic periods. The GCeasy API offers four filtering options: startTime, endTime, startTime and endTime, and beforeEndTime, to facilitate targeted analysis.
In Java 9, GC logging has been overhauled with the Unified GC logging framework (JEP 271), unifying the logging system across JVM components. Consequently, 43 old GC logging flags have been removed, and passing these flags will prevent the JVM from starting, necessitating their replacement. A comparison table of flags is provided.