Book Image

Oracle JRockit: The Definitive Guide

Book Image

Oracle JRockit: The Definitive Guide

Overview of this book

Oracle JRockit is one of the industry’s highest performing Java Virtual Machines. Java developers are always on the lookout for better ways to analyze application behavior and gain performance. As we all know, this is not as easy as it looks. Welcome to JRockit: The Definitive Guide.This book helps you gain in-depth knowledge of Java from the JVM’s point of view. We will explain how to write code that works well with the JVM to gain performance and scalability. Starting with the inner workings of the JRockit JVM and finishing with a thorough walkthrough of the tools in the JRockit Mission Control suite, this book is for anyone who wants to know more about how the JVM executes your Java application and how to profile for better performance.
Table of Contents (23 chapters)
Oracle JRockit
Credits
Foreword
About the Authors
Acknowledgement
About the Reviewers
Preface
12
Using the JRockit Management APIs
Bibliography
Glossary
AST
CAS
HIR
IR
JFR
JMX
JRA
JSR
LIR
MD5
MIR
PDE
RCP
SWT
TLA
Index

Java Memory Model


Since Java is a platform-independent language, care has to be taken when executing the same Java program on different CPU architectures. If bytecode loads and stores were simply mapped to native loads and stores, the semantics of the Java program would change between platforms, usually because some platforms impose stronger memory ordering than others.

In order to guarantee that memory operations in Java are interpreted the same way on different architectures, a Java Memory Model exists. It specifies the semantics of memory accesses in Java. When Java first came out, this model was rather broken, but was later made consistent, through the work of JSR-133.

See also JSR-133.