Java HotSpot Garbage Collection

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The following documents provide information about garbage collection and related issues in the Java HotSpot virtual machine.

Document	Description
Memory Management Whitepaper [pdf]	Includes an overview of GC concepts, descriptions of the available collectors plus some basic tuning tips (more tuning details appear in the tuning guide, below).
Garbage Collector Ergonomics	Describes how the default runtime compiler, garbage collector and heap size are selected. (Note that this document was written for the J2SE 5.0 release; however, the information also applies to Java SE 6.)
Garbage Collection Tuning	Provides details on the available garbage collectors, guidelines for selecting a collector when the default is not satisfactory and suggestions for improving performance by adjusting heap and garbage collection parameters.
How to Handle Java Finalization's Memory-Retention Issues	Describes some of the pitfalls of finalization in Java and presents techniques for avoiding them.
Jon Masamitsu's Weblog	Contains a number of useful nuggets about GC performance and troubleshooting in the Java HotSpot VM.
Garbage First ("G1") Garbage Collector	Provides an introduction to the new G1 garbage collector in the Java HotSpot VM.

Documents for Older Releases
Document	Description
J2SE 5.0 Garbage Collection Tuning	Tuning guide for J2SE 5.0.
J2SE 1.4.2 Garbage Collection Tuning	Tuning guide for J2SE 1.4.2.
Big Heaps and Intimite Shared Memory (Solaris)	Describes how to use the Solaris 8 feature intimate shared memory to improve performance. Note that this technique is not recommended for Solaris 9 and later releases.