Java SE 8 Präsentation im Rahmen der JUG Bielefeld am 12.03.2014.

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