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

Virtualizing Java


Let us now discuss the implications of running an industrial strength Java application server in a virtualized environment. Consider the following figure that illustrates the entire stack from the application server down to the hardware. Between the Java application and the hardware on which it ultimately executes, we have a JVM, a general purpose OS (for example Oracle Enterprise Linux), and a Hypervisor (such as Oracle VM).

The application server, for example Oracle WebLogic, is a typical Java application that needs a JVM to execute. The JVM provides abstraction against the operating system on which the application server is deployed. This is obviously because the same WebLogic shipment should run equally as well on Linux as on Windows or Solaris—this is the whole point of Java. The price of the convenience of write once / run anywhere is thus paid for by the JVM abstraction layer.

Under the JVM is an operating system that the JVM must know how to interact with. This requires...