Memory Management General Rules

This section describes some general rules used by JVM to manage memory.

We know that one strength of JVM (Java Virtual Machine) is that it performs automatic memory management for us. But this also could also give us headaches when JVM throws OutOfMemoryError at us, because we don't have much direct control on how memory is managed.

The only thing we can is to learn how JVM memory management works, write Java code better aligned with the JVM memory management design, and play with JVM memory management parameters for better result. Here are my understandings of HotSpot memory management and suggestions on to avoid OutOfMemoryError exceptions:

The following sections will provide tutorial examples to demonstrate some of these suggestions.

Last update: 2014.

Table of Contents

 About This Book

 Downloading and Installing JDK 1.8.0 on Windows

 Downloading and Installing JDK 1.7.0 on Windows

 java.lang.Runtime Class - The JVM Instance

 java.lang.System Class - The Operating System

 ClassLoader Class - Class Loaders

 Class Class - Class Reflections

 Sun's JVM - Java HotSpot VM

 JRockit JVM 28.2.7 by Oracle Corporation

 JVM Runtime Data Areas

Memory Management and Garbage Collectors

Memory Management General Rules

 Java Exception: "java.lang.OutOfMemoryError: Java heap space"

 OutOfMemoryError Comparison of HotSpot and JRockit

 Garbage Collection Demonstration

 JVM Memory Manager - Garbage Collector

 Generational Garbage Collection in HotSpot

 Young Generation Collection - Minor Collection

 Tenured Generation Collection - Full Collection

 HotSpot Default Garbage Collector - Serial Collector

 "-XX:+PrintGCDetails" - Garbage Collection Logging

 GC Log Messages on

 Serial, Parallel, Concurrent, and Regionalized Collectors

 Parallel Collector GC Log Message Format

 Parallel Compacting Collector GC Log Message Format

 Concurrent Mark-Sweep Collector GC Log Message Format

 Garbage First GC Log Message Format

 Garbage Collection Tests

 JVM Stack, Frame and Stack Overflow

 Thread Testing Program and Result

 CPU Impact of Multi-Thread Applications

 I/O Impact of Multi-Thread Applications

 CDS (Class Data Sharing)

 Micro Benchmark Runner and JVM Options

 Micro Benchmark Tests on "int" Operations

 Micro Benchmark Tests on "long" Operations

 Micro Benchmark Tests in JIT Compilation Mode

 Micro Benchmark Tests on "float" and "double" Operations

 Outdated Tutorials


 PDF Printing Version