Manning Java 8 in Action, Lambdas Streams and Functional-Style Programming

424 Pages·2014·5.65 MB·English

Lambdas, streams, and functional-style programming
IN ACTION
Raoul-Gabriel Urma
Mario Fusco
Alan Mycroft
M A N N I N G
Java 8 in Action

Java 8 in Action
Lambdas, streams, and
functional-style programming
RAOUL-GABRIEL URMA
MARIO FUSCO
ALAN MYCROFT
MANNING
SHELTER ISLAND
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brief contents
PART 1 FUNDAMENTALS ............................................................1
1 ■ Java 8: why should you care? 3
2 ■ Passing code with behavior parameterization 24
3 ■ Lambda expressions 39
PART 2 FUNCTIONAL-STYLE DATA PROCESSING.........................75
4 ■ Introducing streams 77
5 ■ Working with streams 92
6 ■ Collecting data with streams 123
7 ■ Parallel data processing and performance 158
PART 3 EFFECTIVE JAVA 8 PROGRAMMING..............................183
8 ■ Refactoring, testing, and debugging 185
9 ■ Default methods 207
10 ■ Using Optional as a better alternative to null 225
11 ■ CompletableFuture: composable asynchronous
programming 245
12 ■ New Date and Time API 273
vii
viii BRIEF CONTENTS
PART 4 BEYOND JAVA 8 .........................................................289
13 ■ Thinking functionally 291
14 ■ Functional programming techniques 305
15 ■ Blending OOP and FP: comparing Java 8 and Scala 329
16 ■ Conclusions and where next for Java 344
APPENDIXES ............................................................................358
A ■ Miscellaneous language updates 358
B ■ Miscellaneous library updates 362
C ■ Performing multiple operations in parallel
on a stream 370
D ■ Lambdas and JVM bytecode 379
contents
preface xvii
acknowledgments xix
about this book xxi
about the authors xxv
about the cover illustration xxvii
PART 1 FUNDAMENTALS.................................................1
1 Java 8: why should you care? 3
1.1 Why is Java still changing? 5
Java’s place in the programming language ecosystem 6
Stream processing 7 ■ Passing code to methods with
behavior parameterization 9 ■ Parallelism and shared
mutable data 9 ■ Java needs to evolve 10
1.2 Functions in Java 11
Methods and lambdas as first-class citizens 12 ■ Passing code:
an example 13 ■ From passing methods to lambdas 15
1.3 Streams 16
Multithreading is difficult 17
1.4 Default methods 20
1.5 Other good ideas from functional programming 21
1.6 Summary 23
ix