Java GC Tutorials - Herong's Tutorial Examples - v1.11, by Dr. Herong Yang
JVM Garbage Collection Logging
This chapter provides tutorial notes and example codes on JVM options for garbage collection logging. Topics include a summary of logging options; examples of log messages for '-Xlog:gc', '-Xlog:gc:file', -Xlog:gc=trace', '-Xlog:gc+heap=trace', '-Xlog:gc*=trace', etc.
Garbage Collection Demo Program
Garbage Collection Logging Options
"-Xlog:gc" - Default GC Logging Level: INFO
"-Xlog:gc=trace" - Lowest GC Logging Level: TRACE
"-Xlog:gc+heap=trace" - GC+HEAP Log Messages
Takeaways:
Note that GC logging options have been changed since JVM 9. Tutorials in the chapter apply to JVM 9 and newer versions. See tutorials in the next chapter on GC logging options for JVM 8 and older versions.
Table of Contents
Heap Memory Area and Size Control
►JVM Garbage Collection Logging
Introduction of Garbage Collectors
Serial Collector - "+XX:+UseSerialGC"
Parallel Collector - "+XX:+UseParallelGC"
Concurrent Mark-Sweep (CMS) Collector - "+XX:+UseConcMarkSweepGC"
Garbage First (G1) Collector - "+XX:+UseG1GC"
The Z Garbage Collector (ZGC) - "+XX:+UseZGC"
Object References and Garbage Collection
Garbage Collection Performance Test Program
Performance Tests on Serial Collector
Performance Tests on Parallel collector
Performance Tests on Concurrent collector
Performance Tests on G1 collector