Mastering Java 9

441 Pages·2017·13.076 MB·english

by  Edward Lavieri, Peter Verhas

Mastering Java 9
Write reactive, modular, concurrent
and secure code
Dr. Edward Lavieri
Peter Verhas
BIRMINGHAM - MUMBAI
Mastering Java 9
Copyright © 2017 Packt Publishing
First published: October 2017
Production reference: 1031017
Published by Packt Publishing Ltd.
Livery Place
35 Livery Street
Birmingham
B3 2PB, UK.
ISBN 978-1-78646-873-4
www.packtpub.com
Contents
Preface
1
Chapter 1: The Java 9 Landscape
7
Java 9 at 20,000 feet 7
Breaking the monolith 9
Playing around with the Java Shell 10
Taking control of external processes 11
Boosting performance with G1 11
Measuring performance with JMH 11
Getting started with HTTP 2.0 12
Encompassing reactive programming 12
Expanding the wish list 12
Summary 13
Chapter 2: Discovering Java 9
14
Improved Contended Locking [JEP 143] 15
Improvement goals 16
Segmented code cache [JEP 197] 16
Memory allocation 17
Smart Java compilation, phase two [JEP 199] 18
Resolving Lint and Doclint warnings [JEP 212] 18
Tiered attribution for javac [JEP 215] 19
Annotations pipeline 2.0 [JEP 217] 20
New version-string scheme [JEP 223] 22
Generating run-time compiler tests automatically [JEP 233] 22
Testing class-file attributes generated by Javac [JEP 235] 23
Storing interned strings in CDS archives [JEP 250] 25
The problem 25
The solution 26
Preparing JavaFX UI controls and CSS APIs for modularization [JEP
253] 26
JavaFX overview 26
Implications for Java 9 28
Compact strings [JEP 254] 29
Pre-Java 9 status 30
New with Java 9 30
Merging selected Xerces 2.11.0 updates into JAXP [JEP 255] 30
Updating JavaFX/Media to newer version of GStreamer [JEP 257] 31
HarfBuzz Font-Layout Engine [JEP 258] 32
HiDPI graphics on Windows and Linux [JEP 263] 33
Marlin graphics renderer [JEP 265] 34
Unicode 8.0.0 [JEP 267] 34
New in Unicode 8.0.0 34
Updated Classes in Java 9 35
Reserved stack areas for critical sections [JEP 270] 35
The pre-Java 9 situation 35
New in Java 9 36
Dynamic linking of language-defined object models [JEP 276] 37
Proof of concept 38
Additional tests for humongous objects in G1 [JEP 278] 38
Improving test-failure troubleshooting [JEP 279] 40
Environmental information 40
Java process information 41
Optimizing string concatenation [JEP 280] 41
HotSpot C++ unit-test framework [JEP 281] 42
Enabling GTK 3 on Linux [JEP 283] 42
New HotSpot build system [JEP 284] 44
Summary 44
Chapter 3: Java 9 Language Enhancements
45
Working with variable handlers [JEP 193] 46
Working with the AtoMiC Toolkit 47
Using the sun.misc.Unsafe class 49
Eliding depreciation warnings on import statements [JEP 211] 50
Milling Project Coin [JEP 213] 51
Using the @SafeVarargs annotation 51
The try-with-resource statement 52
Using the diamond operator 54
Discontinuing use of the underscore 55
Making use of private interface methods 56
Processing import statements correctly [JEP 216] 58
Summary 60
Chapter 4: Building Modular Applications with Java 9
61
A modular primer 62
Reviewing Java's platform module system [JEP-200] 64
Modularizing JDK source code [JEP-201] 68
Pre-Java 9 JDK source code organization 69
Development tools 70
Deployment 70
Internationalization 70
Monitoring 71
RMI 71
Security 71
Troubleshooting 71
Web services 72
JavaFX tools 72
Java runtime environment 72
Source code 72
Libraries 73
C header files 74
Database 75
JDK source code reorganized 75
Understanding modular run-time images [JEP-220] 75
Runtime format adoption 76
Runtime image restructure 76
Supporting common operations 78
De-privileging JDK classes 78
Preserving existing behaviors 78
Getting to know the module system [JEP-261] 78
Module paths 79
Access-control boundary violations 80
Runtime 80
Modular Java application packaging [JEP-275] 82
Advanced look at the Java Linker 83
Java Packager options 83
JLink - The Java Linker [JEP-282] 87
Encapsulating most internal APIs [JEP-260] 89
Summary 90
Chapter 5: Migrating Applications to Java 9
91
Quick review of Project Jigsaw 92
Classpath 92
The monolithic nature of the JDK 93
How modules fit into the Java landscape 94
Base module 95
Reliable configuration 96
Strong encapsulation 97
Migration planning 98
Testing a simple Java application 98
Potential migration issues 101
The JRE 102
Access to internal APIs 102
Accessing internal JARs 103
JAR URL depreciation 103
Extension mechanism 105
The JDK's modularization 106
Advice from Oracle 107
Preparatory steps 108
Getting the JDK 9 early access build 108
Running your program before recompiling 108
Updating third-party libraries and tools 108
Compiling your application 109
Pre-Java 9 -source and -target options 111
Java 9 -source and -target options 112
Running jdeps on your code 112
Breaking encapsulation 115
The --add-opens option 116
The --add-exports option 116
The --permit-illegal-access option 117
Runtime image changes 117
Java version schema 117
JDK and JRE layout 118
What has been removed 120
Updated garbage collection 121
Deployment 122
JRE version selection 122
Serialized applets 122
JNLP update 123
Nested resources 123
FX XML extension 123
JNLP file syntax 125
Numeric version comparison 125
Useful tools 126
Java environment - jEnv 127
Maven 128
Obtaining the M2Eclipse IDE 129
Summary 132
Chapter 6: Experimenting with the Java Shell
133
What is JShell? 134
Getting Started with JShell 134
Practical uses of JShell 140
Feedback modes 141
Creating a custom feedback mode 146
Listing your assets 148
Editing in the JShell 149
Modifying text 149
Basic navigation 150
Historical navigation 150
Advanced editing commands 151
Working with scripts 151
Start up scripts 151
Loading scripts 152
Saving scripts 152
Advanced scripting with JShell 153
Summary 154
Chapter 7: Leveraging the New Default G1 Garbage Collector
155
Overview of garbage collection 156
Object life cycle 156
Object creation 156
Object mid-life 157
Object destruction 157
Garbage collection algorithms 158
Mark and sweep 158
Concurrent mark sweep (CMS) garbage collection 158
Serial garbage collection 159
Parallel garbage collection 159
G1 garbage collection 159
Garbage collection options 160
Java methods relevant to garbage collection 165
The System.gc() method 166
The finalize() method 168
Pre-Java 9 garbage collection 169
Visualizing garbage collection 170
Garbage collection upgrades in Java 8 171
Case study - Games written with Java 172
Collecting garbage with the new Java platform 173
Default garbage collection 173
Depreciated garbage collection combinations 175
Unified garbage collection logging 176
Unified JVM logging (JEP-158) 177
Tags 177
Levels 178
Decorations 178
Output 179
Command-line options 179
Unified GC logging (JEP-271) 179
Garbage collection logging options 180
The gc tag 182
Macros 182
Additional considerations 183
Persistent issues 184
Making objects eligible for garbage collection 184
Summary 187
Chapter 8: Microbenchmarking Applications with JMH
188
Microbenchmarking overview 189
Approach to using JMH 190
Installing Java 9 and Eclipse with Java 9 support 190
Hands-on experiment 193
Microbenchmarking with Maven 195
Benchmarking options 202
Modes 203
Time units 203
Techniques for avoiding microbenchmarking pitfalls 204
Power management 204
OS schedulers 204
Time sharing 205
Eliminating dead-code and constant folding 205
Run-to-run variance 206
Cache capacity 207
Summary 207
Chapter 9: Making Use of the ProcessHandle API
208
What are processes? 209
The new ProcessHandle interface 210
Getting the PID of the current process 210
Getting information about a process 211
Listing processes 213
Listing children 213
Listing descendants 214
Listing all processes 215
Waiting for processes 216
Terminating processes 217
A small process controller application 219
Main class 220
Parameters class 221
The ParamsAndHandle class 222
The ControlDaemon class 223
Summary 226
Chapter 10: Fine-Grained Stack Tracing
227
Overview of the Java Stack 227
The importance of stack information 228
Example - Restricting callers 230
Example - Getting logger for caller 233
Working with StackWalker 234
Getting an instance of StackWalker 234
RETAIN_CLASS_REFERENCE 234
SHOW_REFLECT_FRAMES 235
SHOW_HIDDEN_FRAMES 235
Final thoughts on enum constants 238
Accessing classes 238
Walking methods 239
StackFrame 241
Performance 242
Summary 242
Chapter 11: New Tools and Tool Enhancements
243
The new HTTP client [JEP-110] 244
The HTTP client before Java 9 244
Java 9's new HTTP client 247
New API limitations 248
Simplified Doclet API [JEP-221] 250
The pre-Java 9 Doclet API 250
API enums 252
API classes 252
API interfaces 253
Problems with the pre-existing Doclet API 254
Java 9's Doclet API 254
Compiler tree API 254
Language model API 258
The AnnotatedConstruct interface 259
The SourceVersion enum 259
The UnknownEntityException exception 261
HTML5 Javadoc [JEP-224] 262
Javadoc search [JEP-225] 267
Introducing camel case search 268
Remove launch-time JRE version selection [JEP-231] 268
Parser API for Nashorn [JEP-236] 269
Nashorn 269
Using Nashorn as a command-line tool 270
Using Nashorn as an embedded interpreter 273
EMCAScript 274
Parser API 275
Multi-release JAR files [JEP-238] 277
Identifying multi-release JAR files 277
Related JDK changes 279
Java-level JVM compiler interface [JEP-243] 280
BeanInfo annotations [JEP-256] 281
JavaBean 281
BeanProperty 282
SwingContainer 283
BeanInfo classes 283
TIFF image input/output [JEP-262] 284
Platform logging API and service [JEP-264] 286
The java.util.logging package 287
Logging in Java 9 289
XML Catalogs [JEP-268] 290
The OASIS XML Catalog standard 290
JAXP processors 291
XML Catalogs prior to Java 9 291
Java 9 platform changes 291
Convenience factory methods for collections [JEP-269] 291
Using collections before Java 9 292
Using new collection literals 295
Platform-specific desktop features [JEP-272] 295
Enhanced method handles [JEP-274] 296
Reason for the enhancement 297
Lookup functions 297
Argument handling 298
Additional combinations 298
Enhanced deprecation [JEP-277] 299
What the @Deprecated annotation really means 300
Summary 300
Chapter 12: Concurrency and Reactive Programming
301
Reactive Programming 302