Java Performance and Scalability

Presented in 48 concise lessons that target the most common and critical performance pitfalls, this book offers a plethora of practical tips and solutions for boosting the performance of your programs. These lessons cover performance-critical areas such as memory management, garbage collection, caching, and multithreading.

Specific lessons include:

• Reserving StringBuffer capacity
• Avoiding premature object creation
• Creating an efficient vector class
• Designing caching into your API
• The cost of synchronization
• Parallel subtasks
• JNI efficiency
• Varying the server workload and RMI network plumbing
• Using ServletOutputStream
• Caching JDBC? connections

In addition to providing hard numbers that quantify the optimizations, the author concludes the book with an application demonstrating the effectiveness of the performance optimizations. The exercise takes a typical program and increases its performance fourfold through a series of steps that tie together the lessons learned throughout the book. He offers both the means and the proof to better coding.

Table of contents

List of Figures

Preface

Introduction

1 Java Strings

Optimization 1: String Concatenation

Optimization 2: Fight Object Overpopulation

Optimization 3: String Equality

Optimization 4: Characters to Bytes and Back

Optimization 5: StringTokenizer

Optimization 6: charAt()

Optimization 7: Prefer charAt() to startsWith()

Optimization 8: Reserve StringBuffer Capacity

Key Points

2 Pure Overhead

Optimization 9: Useless Computations

Optimization 10: Don't Trace Trivial Methods

Optimization 11: Making Overhead Vanish

Optimization 12: Premature Object Creation

Optimization 13: Don't Initialize Twice

Optimization 14: Do You Really Need to Zero-Out a Buffer?

Optimization 15: The 80-20 Principle

Optimization 16: Purge Obsolete Code

Key Points

3 Vectors and Hashtables

Optimization 17: Vector Add and Remove

Optimization 18: Vector Capacity

Optimization 19: Vector Enumeration

Optimization 20: Efficient Vector Class

Optimization 21: Using the API Wisely

Optimization 22: Hashtable Parameters

Optimization 23: Speed Up hashCode()

Optimization 24: Speed Up equals()

Key Points

4 Caching

Optimization 25: Cache File Contents

Optimization 26: Design Caching into Your API

Optimization 27: Precompute

Optimization 28: Relax Granularity

Optimization 29: Inheritance

Key Points

5 I/O Streams

Example I/O Code

Optimization 30: Output Buffering

Optimization 31: Don't Flush Prematurely

Optimization 32: Prefer Byte Stream to Unicode

Optimization 33: Input Buffering

Optimization 34: Byte-to-Char Conversions

Optimization 35: Binary I/O

Key Points

6 Recycling

Optimization 36: Object Recycling

Optimization 37: Object Pools

Optimization 38: Last In, First Out

Key Points

7 Scalability and Multithreading

Scalability Basics

The SMP Architecture

Amdahl's Law

Multithreaded and Synchronization Terminology

The Cost of Synchronization

Optimization 39: Parallel Subtasks

Optimization 40: Synchronization False Sharing

Optimization 41: Lock Fusion

Optimization 42: Code Motion

Optimization 43: Share Nothing

Optimization 44: Partial Sharing

Optimization 45: Read/Write Locks

Key Points

8 JNI

Optimization 46: JNI Surprise

Optimization 47: JNI to the Rescue

Optimization 48: Prefer System.arraycopy()

Key Points

9 RMI

The RMI Network Plumbing

Varying the Server Workload

RMI Server on Remote Machine

Serializing Heavyweight Objects

Key Points

10 Servlets

Servlets Using PrintWriter

Servlets Using ServletOutputStream

Precomputing Message Bytes

Pumping More Data

PingServlet--A Performance Upper Bound

Extending PingServlet

Session State

PingJdbc

Caching JDBC Connections

JSP--Java Server Pages

RMI

Key Points

11 A Java Web Server

Version 1: The Original Server

Version 2

Version 3

Version 4

Version 5

Version 6

Key Point

A Caching JDBC Connections

CacheDriver.java

CacheConnection.java

CacheStatement.java

CacheCallableStatement.java

CachePreparedStatement.java

CacheDriver.properties

B Simple Java Web Server

Server.java

FileInfo.java

UrlCache.java

LazyDate.java

MyGetBytes.java

server.properties

Bibliography

Index