What’s new in java 8

1. WHAT’S NEW IN JAVA 8

2. ABOUT ME Rajmahendra Hegde (Raj)
• Working for ValueLabs as Scrum Master/Project
Lead
• 14 years Java development
• JUG Hyderabad Lead
• NetBeans Dream Team Member
• JCP Individual and Expert Group Member for 3
JSRs
• Comitter / Contributor: JBake, Forge, NetBeans,
eWidgetFX, JavaFX, Gradle, Agorava, JRebirth,
ScalaFX
Twitter: @rajonjava
GitHub: rajmahendra
LinkedIn: rajmahendra

3. AGENDA
 Lambda
 Streams
 Date & Time
 Nashorn
 Java FX

4. JAVA LAMBDA !
Java with functional style.

5. JAVA LAMBDA
 Beginning of Functional flavor into Java platform
 Lambda provides anonymous function to Java
 Replaces the old use of Anonymous inner classes
 Write more compact code
 Parallel programming easier

6. ANONYMOUS INNER CLASS

7. LAMBDAFIDE ANONYMOUS INNER CLASS

8. LAMBDA EXPRESSION
 ( ) ->
 ( ) -> { }
 a -> a
 x -> { int y=4; return x * y; }

9. LAMBDA & FUNCTIONAL INTERFACE
 Functional interface are interface with only one
method.
 Java space is filled of such Interfaces
 java.lang.Runnable.run();
 java.util.Comparator.compare(T a, Tb);
 java.awt.event.ActionListener.actionPerformed(
ActionEvent e)

10. JAVA8 LAMBDA PACKAGE
 Additionally Java8 also provides
FunctionalInterface in package java.util.function to
use with Lambdas. This package contains more
than 40 commonly used FI
 Predicate<T>.test(T t) - Represents a predicate
(boolean-valued function) of one argument
 Consumer<T>.accept(T t) - Represents an operation
that accepts a single input argument and returns no
result
 Function<T, R>.R accept(T t) - Represents a function
that accepts one argument and produces a result
 Supplier<T>. T get() -Represents a supplier of results
 …

11. @FUNCTIONALINTERFACE
 FunctionalInterface = Interface with only one
method
 Annotation is optional. Its only to make sure the
interface is a FunctionalInterface
 Any interface with only one method can be
considered as FunctionalInterface

12. LAMBDA TO LOCAL VARIABLE

13. VARIABLE CAPTURE
 Lambda can interact with the variable outside of its
body
 Using the variables outside of the Lambda
expression is called Variable Capture
 Effectively final

14. LAMBDA VS ANONYMOUS INNER CLASS
 Lambda != Anonymous Inner Class
 Inner class can have state
 Inner class can have multiple methods
 this points to the object instance in a inner class
but points to the enclosed object in Lambda
 Lambda != Anonymous Inner Class

15. METHOD REFERENCE
 Use method reference when you use Lambda
expression
 Reduces boilerplate code
 NOTE: return type of lambda expression must
match with the signature of the referred method

16. METHOD REFERENCE TYPES
 Static Method
 Printer::print
 Instance Method
 myObject::print
 Constructor
 Page::new

17. DEFAULT METHOD - INTERFACE
 Provides a way to add new methods to interface
without breaking the old implementation
 default keyword is introduced to do this magic

18. NO MORE NULLPOINTEREXCEPTION !
 Wrapper class to guard from Null Exception
 java.util.Optional<T>
 It contain a data or a empty

19. STREAMS

20. STREAMS
 Streams are functional programming design pattern
 Helps in processing sequential elements as
sequentially or parallel
 In java we use in many different places
 Retrieve database query as list objects
 Iterate over xml or json elements
 Read multiple lines
 Collections, map etc.

21. STREAMS IN JAVA
 To create a stream you use a Source collection
 Add a filter option to the stream Intermediate
operation pipeline
 And ends with Terminal operation which starts the
stream process

22. STREAM LIFECYCLE
 Creation – Stream is created with the collection
object from source
 Configure – get configured with the list of pipeline
operators
 Execution – Streams Terminal operation triggers
the stream to starts by pulling objects into the
pipeline
 Cleanup

23. DATE & TIME API

24. OLD DATE/TIME API
 java.util.Date
 java.sql.Date
 java.util.Calendar
 java.util.GregorianCalendar
 java.util.TimeZone
 java.text.DateFormat
 java.text.SimpleDateFormat

25. ISSUES WITH OLD API
 All are just utility class (in java.util package or in
java.text)
 Date class contains both Date and Time
 Different Date class for SQL!
 Date doesn't have timezone
 Month is zero based, year is 1900 based.
 Not thread safe by default
 Arithmetic operations are hard to use

26. DATE AND TIME API
 New dedicated date time package java.time
 Dedicated class for Date and time LocalDate and
LocalTime
 A composite class for both LocalDateTime
 Numerous way to create Date time objects
 Support for Truncation, TimeZones, Periods,
Durations and Chronologies
 More fluent, clean and simple API
 Immutable classes

27. LOCALDATE
 Year-Month-Day
 Only for Date manipulation
 Stores or create one particular Date

28. LOCALTIME
 Hours-Minutes-Seconds-nano

29. LOCALDATETIME
 Combination of LocalDate & LocalTime
 All methods of both class available

30. TIMEZONE
 Numerous timezones are available
 Some time complex to manipulate
 Some time it may change frequently
 TimeZone Classes
 ZoneId – Europe/London etc.
 ZoneOffset – offset from UTC time
 ZoneRules – defines timezone rules
 ZonedDateTime – TimeZone aware Datetime class

31. DURATION
 Time based amount of time

32. PERIOD
 Date based amount of time

33. NASHORN

34. NASHORN
 Nashorn is a JavaScript Engine developed on Java
 Light-weight, high-performance integrated into JRE
 ECMAScript-262 Edition 5.1 language specification
compliance
 Java 8 shipped with a command-line tool called jjs
 JDK 6 already shipped with Mozilla’s Rhino
JavaScript Engine.

35. CALLING JAVASCRIPT FROM JAVA

36. CALLING JAVA FROM JAVASCRIPT

37. JAVAFX
• http://www.slideshare.net/rajmahendra/javafx-2-rich-
desktop-platform
• http://www.slideshare.net/Codemotion/codemotion-
whatsnewforjavafxinjdk8

38. JAVA 9!
 September 22nd 2016
 Timeline
 2015-12-10 Feature Complete
 2016-02-04 All Tests Run
 2016-02-25 Ramp down Start
 2016-04-21 Zero Bug Bounce
 2016-06-16 Ramp down Phase 2
 2016-07-21 Final Release Candidate
 2016-09-22 General Availability
 Project Jigsaw
 REPL
 …

39. Q & A
Rajmahendra Hegde
http://meetup.com/jughyderabad
Twitter: @rajonjava GitHub: rajmahendra
LinkedIn: rajmahendra SllideShare: rajmahendra

40. Rajmahendra Hegde
http://meetup.com/jughyderabad
Twitter: @rajonjava GitHub: rajmahendra LinkedIn: rajmahendra SllideShare: rajmahendra