Java GC Tutorials - Herong's Tutorial Examples - v1.11, by Dr. Herong Yang
Java GC Tutorials - Herong's Tutorial Examples
https://www.herongyang.com/Java-GC
Copyright © 2022 Dr. Herong Yang. All rights reserved.
This book is a collection of tutorial notes and sample codes written by the author while he was learning JVM GC (Garbage Collection) processes. Topics include Java Garbage Collectors, STW (Stop-The-World), Serial Collector, Parallel Collector, Concurrent Collector, G1 Collector, GC Algorithms, Generational GC, Regional GC, Heap Memory Management, Young/New Generation, Tenured/Old Generation, Object Reference, Eden Space, Survivor Spaces, Minor GC, Major GC, Full GC, Performance Tuning, Throughput/Latency Performance, Heap Footprint. Updated in 2022 (Version v1.11) with JVM 17.
Table of Contents
Heap Memory Area and Size Control
Java Exception: "java.lang.OutOfMemoryError: Java heap space"
Memory Allocation Limits on Windows Systems
OutOfMemoryError Comparison of HotSpot and JRockit
JVM Garbage Collection Logging
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
"-Xlog:gc*=trace" - Maximum GC Logging
"-XX:+PrintFlagsFinal" - Print JVM Options
Introduction of Garbage Collectors
JVM Memory Manager - Garbage Collector
Generational Garbage Collection in HotSpot
Young Generation Collection - Minor GC
Young Generation Collectors - Serial, PS, ParNew, G1
Tenured Generation Collection - Major GC
Tenured Generation Collectors - Serial, ParOldGen, CMS, G1
Collector Combinations: Serial, Parallel, Concurrent, G1, Z
Serial Collector - "+XX:+UseSerialGC"
GC Log Message Format for Serial Collector
GC Log Message Examples of Serial Collector
Log Message Types from Serial Collector
Serial Collector Stops Application for Minor/Major GC
Usage Report on Heap Memory Areas
Default NewRatio - Old vs. New Generation
"-XX:NewRatio" - Ratio of Tenured and "new" Generation
"-XX:SurvivorRatio" - Ratio of Eden and Survivor Space
Serial GC Tracing - Tight Heap
Serial GC Tracing - Tight Heap (Part 2)
Serial GC Tracing - Tight Heap (Part 3)
Serial GC Tracing - Plenty of Heap
Serial GC Tracing - Aged Live Objects
Serial GC Tracing - Tenuring Threshold
"-XX:TargetSurvivorRatio" - Second Tenuring Condition
Serial GC Tracing - Tenuring Threshold Controlled
"-XX:+NeverTenure" and "-XX:+AlwaysTenure" Working
Minor GC Triggering Condition of Serial Collector
Parallel Collector - "+XX:+UseParallelGC"
Parallel Collector GC Log Message Format
Log Message Types from Parallel Collector
"--Xlog:gc+task+time=debug" - Print GC Threads
"-XX:ParallelGCThreads" - # of Threads
Parallel Collector Stops Application for Minor/Major GC
PSYoungGen Collector Using Tenuring Age
Parallel Collector Changing NewRatio and SurvivorRatio
Parallel Collector Adaptive Size Policy
Adaptive Size Policy Log Messages
"-Xlog:gc+ergo=trace" - Minor GC Report
Adaptive Size Policy Changed Survivor Space
Adaptive Size Policy Changed Eden Space
Adaptive Size Policy for Best Latency
Parallel Collector Stopped using Young Generation
Adaptive Size Policy for Best Throughput
Concurrent Mark-Sweep (CMS) Collector - "+XX:+UseConcMarkSweepGC"
What Is Concurrent Mark-Sweep (CMS) Collector
Concurrent Mark-Sweep Collector GC Log Message Format
Reduce Stop-The-World with Concurrent Mark and Sweep
Parallel New (ParNew) Collector for Minor GC
ParNew Collector - Tenuring Age Distribution
Maximum Logging of All Phases on Young GC
"-XX:ParallelGCThreads=6" - Young GC Parallel Threads
"-XX:MaxTenuringThreshold=0" - Tenuring Objects Immediately
"-XX:CMSInitiatingOccupancyFraction=20" - Initiate CMS
Maximum Logging of All Phases on Old GC
Maximum Logging of All Phases on Full GC
"-XX:ParallelGCThreads=6" - Old GC Parallel Threads
"-XX:ConcGCThreads=3" - Old GC Concurrent Threads
Garbage First (G1) Collector - "+XX:+UseG1GC"
The Z Garbage Collector (ZGC) - "+XX:+UseZGC"
Object References and Garbage Collection
Garbage Collection Performance Test Program
GCPerformance.java - GC Performance Test Program
GCPerformance.java - Program Output
Performance Impact of Wait Time
Performance Impact of Object Size
Performance Impact of Chunk Size
Performance Jumps Not Related to GC
Performance Test and System Interruptions
"START /REALTIME" - Run JVM with Highest Priority
GCPerfP99.java - 99th Percentile Performance
GCPerfP99.java - Output Verification
GCPerfP99V2.java - Percentile Performance with Load
GCPerfP99V2.java - Work Load Level
GCPerfP99V2.java - Object Number and Size
Performance Tests on Serial Collector
Performance Tests on Parallel collector
Performance Tests on Concurrent collector
Performance Tests on G1 collector
Garbage Collection Performance Test Summary
Keywords: Java, Virtual, Machine, JVM, GC, Garbage Collection