This document summarizes a presentation about new features in Java SE 8. It discusses lambda expressions, default methods, stream API for collections, and improvements to core libraries, garbage collection, and security. The presentation covers over 50 new features and improvements in Java 8 and includes code examples of using lambda expressions, method references, and the stream API.

1. Java SE 8 Features
Neuerungen in Java SE 8
pr sentiert von Sascha Kochä
12. M rz 2014ä
JUG Bielefeld

2. 12.03.2014 Java SE 8
Alle freuen sich auf Java 8
Quelle www.heise.de

3. 12.03.2014 Java SE 8
Programm f r heute abendü
● > 50 Neuerungen in Java SE 8
● Hands-on Session mit λ-Expressions, der
Stream API, den default methods und mehr

4. 12.03.2014 Java SE 8
Java 8 JEPs General
● 126 Lambda Expressions & Virtual Extension Methods
(aka defender or default methods)
● 138 Autoconf-Based Build System (for the jdk itself)
● 160 Lambda-Form Representation for Method Handles
(reduce assembly code and native calls, performance optimization, reference implementation
of invokedynamic / JSR-292)
● 161 Compact Profiles (instead of jigsaw 140/24/17/10 MB)→
● 162 Prepare for Modularization
(getting ready for jigsaw, java.util.logging and swing)

5. 12.03.2014 Java SE 8
Java 8 JEPs General
● 164 Leverage CPU Instructions for AES Cryptography
(Intel M rz 2008)ä
● 174 Nashorn JavaScript Engine
(lightweight, high-performance, ECMAScript-262 5.1)
● 176 Mechanical Checking of Caller-Sensitive Methods
(improve security of method-handle implementation, behaviour changed based on the caller)
● 179 Document JDK API Support and Stability
(mark core and non-core APIs, what is maintained?)

6. 12.03.2014 Java SE 8
Java 8 JEPs Core
● 153 Launch JavaFX Applications
(launch() from java cmd line)
● 101 Generalized Target-Type Inference Code
(only partly realized)
● 104 Annotations on Java Types Code
(applied to any use of a type, not at runtime :( )
● 105 DocTree API (provide structured access to javadoc content)
● 106 Add Javadoc to javax.tools
(call javadoc from within vm)

7. 12.03.2014 Java SE 8
Java 8 JEPs Core
● 117 Remove the Annotation-Processing Tool (in javac)
● 118 Access to Parameter Names at Runtime Code
(partly realized)
●
120 Repeating Annotations Code
(avoid container annotations, somehow)
● 139 Enhance javac to Improve Build Speed
(use of all available cores)
●
172 DocLint Code
(static doc analysis, Fusselig, W3C HTML 4.01 HTML conform)

8. 12.03.2014 Java SE 8
Java 8 JEPs Garbage Collection
● 142 Reduce Cache Contention on Specified
Fields
(pad variables to avoid sharing cache lines)
● 122 Remove the Permanent Generation
(Permanently, PermGen moves to native memory)
●
173 Retire Some Rarely-Used GC Combination
(e.g. ParNew + SerialOld, reduce testing effort)

9. 12.03.2014 Java SE 8
Java 8 JEPs Garbage Collection
● 142 Reduce Cache Contention on Specified
Fields
(pad variables to avoid sharing cache lines)
● 122 Remove the Permanent Generation
(Permanently, PermGen moves to native memory)
●
173 Retire Some Rarely-Used GC Combination
(e.g. ParNew + SerialOld, reduce testing effort)

10. 12.03.2014 Java SE 8
Java 8 JEPs Runtime
● 136 Enhanced Verification Errors
(additional information bytecode verification errors)
● 147 Reduce Class Metadata Footprint
(taken from ME)
● 148 Small VM
(libjvm.so < 3MB, compiling size over speed)
● 171 Fence Intrinsics
(sun.misc.Unsafe, memory access)

11. 12.03.2014 Java SE 8
Java 8 JEPs Core Libraries
●
103 Parallel Array Sorting (new methods in java.util.Arrays)
● 107 Bulk Data Operations for Collections
(java.util.function, java.util.stream)
●
109 Enhance Core Libraries with Lambda
(Java SE 7 has 4024 standard classes)
●
112 Charset Implementation Improvements
(fewer, quicker, better)
●
119 javax.lang.model Implementation Backed by Core
Reflection

12. 12.03.2014 Java SE 8
Java 8 JEPs Core Libraries
● 135 Base64 Encoding & Decoding
(previously in sun.misc.*, now java.util.*)
● 149 Reduce Core-Library Memory Usage
(reduce dynamic memory)
● 150 Date & Time API
(Wurde auch Zeit!)
● 155 Concurrency Updates
(Doug Lea Stuff)
● 170 JDBC 4.2 (new Date API support)

13. 12.03.2014 Java SE 8
How many Bugs?
Date date = new Date(2014, 12, 24, 16, 40);
TimeZone zone =
TimeZone.getTimeZone(“Asia/HongKong”);
Calendar cal =
new GregorianCalendar(date, zone);
DateFormat fm =
new SimpleDateFormat(“HH:mm Z”);
String str = fm.format(cal);

14. 12.03.2014 Java SE 8
How many Bugs? 6!
Date date = new Date(114, 11, 24, 16, 40);
TimeZone zone =
TimeZone.getTimeZone(“Asia/Hong_Kong”);
Calendar cal = new GregorianCalendar(zone);
cal.setTime(date);
DateFormat fm =
new SimpleDateFormat(“HH:mm Z”);
fm.setTimeZone(zone);
Date calDate = cal.getTime();
String str = fm.format(calDate);

15. 12.03.2014 Java SE 8
Java 8 JEPs Diverses
● 177 Optimize java.text.DecimalFormat.format
(2 x faster for 2 or 3 digits after decimal point)
● 178 Statically-Linked JNI Libraries
(previously only dynamically linked)
●
180 Handle Frequent HashMap Collisions with
Balanced Trees
(performance improvement, previously with linked lists)
●

16. 12.03.2014 Java SE 8
Java 8 JEPs Diverses
●
127 Improve Locale Data Packaging and Adopt
Unicode CLDR Data
(standardized locale support)
● 128 BCP 47 Locale Matching
(as defined in rfc-4647)
●
133 Unicode 6.2
● 184 HTTP URL Permissions (previously based on IP addresses)

17. 12.03.2014 Java SE 8
Java 8 Security
● 113 MS-SFU Kerberos 5 Extensions
(Microsoft interoperability)
●
114 TLS Server Name Indication (SNI) Extension (new feature)
●
115 AEAD CipherSuites (meet US government and banking requirements)
● 121 Stronger Algorithms for Password-Based Encryption
(evolution of cryptography, PBEwith*, previously DESede and RC2 with SHA1)
● 123 Configurable Secure Random-Number Generation
(/dev/random Entropie unter Linux ist alle)→
●
124 Enhance the Certificate Revocation-Checking API
(more complete,flexible)

18. 12.03.2014 Java SE 8
Java 8 Security
●
129 NSA Suite B Cryptographic Algorithms
(meet US government and banking requirements)
● 130 SHA-224 Message Digests (known flaw in SHA-1)
● 131 PKCS#11 Crypto Provider for 64-bit Windows
(use of native Win64 libraries)
●
140 Limited doPrivileged (Lambda expressions)
● 166 Overhaul JKS-JCEKS-PKCS12 Keystores
(simplification of keystore handling)

19. 12.03.2014 Java SE 8
Java 8 JEPs / Web JAXP
● 185 JAXP 1.5: Restrict Fetching of External
Resources
(restrict the set of network protocols used to fetch external resources)

20. 12.03.2014 Java SE 8
Lambda Expressions
● Aka closures, function literals or Lambdas
● From anonymous inner classes to FunctionalInterfaces;
previously known as SAM (single abstract method)
●
Syntax:
1. argument list enclosed in parentheses
2. an arrow token ( )→
3. a function body

21. 12.03.2014 Java SE 8
Default methods
● Interfaces can have default implementations
● Method starts with default

22. 12.03.2014 Java SE 8
Lambda form representation
method handles
● object::instanceMethod
Arrays.asList(0, -2, 2).forEach(System.out::println);
Arrays.asList(0, -2, 2).forEach((x) System.out.println(x));→ →
● Class::staticMethod
Arrays.asList(0, -2, 2).sort(Integer::compare);
Arrays.asList(0, -2, 2).sort((x, y) Integer.compare(x, y));→ →
● Class::instanceMethod
Arrays.asList(0, -2, 2).sort(Integer::compareTo);
Arrays.asList(0, -2, 2).sort((x, y) x.compareTo(y));→ →

23. 12.03.2014 Java SE 8
Collection vs Stream
Quelle: wikimedia.org

24. 12.03.2014 Java SE 8
Stream-API
●
Get a stream from a collection
collection<E>.stream();
●
Generate, limit and skip a stream
Stream.generate(Supplier<T> s) // static
stream<T>.limit(long)
stream<T>.skip(long)
●
Manipulate a stream
stream<T>.map(Function<T, R>) Stream<R>→
stream<T>.filter(Predicate<T>) Stream<T>→
stream<T>.sorted() Stream<T>→
stream<T>.distinct() Stream<T>→

25. 12.03.2014 Java SE 8
Stream-API
● “Collection a result” of a stream
stream<T>.allMatch(Predicate<T>) boolean→
stream<T>.anyMatch(Predicate<T>) boolean→
stream<T>.findAny() Optional<T>→
stream<T>.findFirst() Optional<T>→
stream<T>.max(Comparator<T>) Optional<T>→
stream<T>.min(Comparator<T>) Optional<T>→
stream<T>.reduce(T, BinaryOperator<T>) T→
stream<T>.collect(T, A, R) R→

26. 12.03.2014 Java SE 8
Stream-API
● Default Collectors
Collectors.toList() Collector<T, ?, List<T>>→
Collectors.reducing(T, BinaryOperator<T>) T→
Collectors.joining() Collector<CharSeq, ?, String>→
Collectors.counting() Collector<T, ?, Long>→

27. 12.03.2014 Java SE 8
Danke!

28. 12.03.2014 Java SE 8
Referenzen
● http://www.youtube.com/watch?v=rtAredKhyac, Simon Ritter
● Java SE 8 for the Really Impatient, Cay S. Horstmann
● Java 8 in Action, Raoul-Gabiel Urma et.al
● http://openjdk.java.net/projects/jdk8/features