engage 2016 - Get ready for moving from Java 6 to Java 8 - Now!
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These slides have been shown at engage.ug 2016 in Eindhoven. They show a brief introduction in some of the new Java 8 features.
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engage 2016 - Get ready for moving from Java 6 to Java 8 - Now!
- 1. 1 Get ready for moving from Java 6 to Java 8 – Now! René Winkelmeyer 24.03.2016
- 2. 2 • Skype / Twitter / LinkedIn / Slideshare muenzpraeger • Web https://blog.winkelmeyer.com • Mail mail@winkelmeyer.com OpenNTF • File Navigator • Generic NSF View Widget for IBM Connections About me René Winkelmeyer Head of Development
- 3. 3 YES – I CAN!
- 4. 4 A timeline perspective § Quick poll § IBM Notes/Domino development? § WebSphere development? § Java 6 only development? § Java 7+ only development? § Mixed Java version development?
- 6. 6 A timeline perspective Java 6 23.12.2006 Java 7 28.07.2011 Java 8 18.03.2014 Java 9 23.03.2017 Javaversionsby releasedate IBM Notes/ Domino IBM WebSphere (Full Profile) IBM WebSphere (Liberty Profile) SupportedJava version byproduct
- 7. 7 What this session covers § Switch-strings § Diamonds § Paths § Lambdas § Streams § Date/Time
- 8. 8 Goodbye if-then-elseif-elseif-elseif… for Strings
- 9. 9 Goodbye if-then-elseif-elseif-elseif… for Strings Way in Java 6 and smaller to check for different String types
- 10. 10 Goodbye if-then-elseif-elseif-elseif… for Strings § Java 7 added support for java.lang.String in switch § Increased readability § Produces more efficient byte code § Switching based on the hashcode() § May (still) throw a NullPointerException
- 11. 11 Goodbye if-then-elseif-elseif-elseif… for Strings Now a clean way. Alternative could be to use Enums (also prior Java 7).
- 12. 12 Diamonds are developers best friends
- 13. 13 Diamonds are developers best friend § Java 7 introduced the usage of the <> operator for type inference § Removes verbose code § Makes usage of 3rd party libs like Google Guava for List creation obsolete
- 14. 14 Diamonds are developers best friend Raw error warning in Eclipse. Technically possible, but not recommended. How to do it. Imagine HashMap<String, HashMap<String, Object>> i. e. Diamond operator for less code writing. ;-)
- 16. 16 Automated resource management (simple) Close in finally Multiple exceptions to catch Init outside the try to close it later
- 17. 17 Automated resource management § Java 7 introduced the new java.lang.AutoCloseable interface § Resources that inherit from this interface are automatically closed when created within a try statement § Reduces boilerplate code drastically § java.lang.Closeable extends from java.lang.AutoCloseable § AutoCloseable.close() shouldn‘t be called twice!
- 18. 18 Automated resource management (simple) Close in finally Multiple exceptions to catch Init outside the try to close it later
- 19. 19 Automated resource management (simple) No finally, no close()
- 20. 20 Automated resource management (more) Multiple streams to close Multiple streams to handle Multiple streams to close
- 21. 21 Automated resource management (more) „Join“ multiple AutoCloseables with a ; separator within the try statement
- 22. 22 Underscore me
- 23. 23 Underscore me § You‘ve two seconds to identify these numbers
- 24. 24 Underscore me § The with Java 7 introduced capability allows to add underscores to numeric types (int, double, long). § A few rules to obey: § Can be used after the decimal point, but not directly before/after it § No underscores at the end or the beginning (i. e. _5000 or 5000_)
- 25. 25 Underscore me § You‘ve two seconds to identify these numbers
- 26. 26 Underscore me § You‘ve two seconds to identify these n_e_w numbers
- 27. 27 Catch me if you can
- 28. 28 Catch me if you can One catch per named exception
- 29. 29 Catch me if you can multi-catch has been introduced with Java 7
- 30. 30 NIO.2
- 31. 31 NIO.2 § The handling of file system related actions has been much improved with Java 7. § Removes the need in a lot of cases to rely on 3rd pary libraries like Apache Commons Files. § Direct implementation in the base JDK
- 32. 32 NIO.2 § java.nio.Path § Think of it as a replacement for java.io.File § Represents a file or a folder – and it doesn‘t need to exist (no Exception ;-)) § java.nio.Files § Loads of utility classes for file and folder handling
- 33. 33 Make your Path (and more)
- 34. 34 Make your Path (and more)
- 35. 35 Watch your files Initiates the default WatchService as introduced with Java 7 Assign the to be monitored path using the new java.nio.Path API Register the created WatchService with the path. Events that can be monitored are create, update and delete.
- 36. 36 Watch your files Holds the results of the monitored events Map of all found events
- 37. 37 default
- 38. 38 default § Changes in Interfaces always led to changes in the classes they used them § The new default constructor introduces „backward“ compatibility
- 39. 39 Before Java 8
- 40. 40 Before Java 8 Adding a new Interface method Compilation error on all classes that implement the Interface
- 41. 41 With Java 8 Method body needed
- 42. 42 With Java 8 Calling a duplicate default method
- 43. 43 Lambdas
- 44. 44 Lambdas § One of the biggest changes with Java 8 § Known from other languages like Closure, Scala, C# and more § Defined in Java Specification Request (JSR) 335 § Knows as closures or functional literals in other languages § Love or hate them – there‘s no way around them!
- 45. 45 Lambdas Standard boilerplate code to iterate Sequential, not parallel!
- 46. 46 Lambdas Anonymous methods to the rescue but ... Have you spotted the forEach?
- 47. 47 Lambdas Calling the anonymous inner method directly via a lambda call
- 48. 48 Lambdas Shorten it even more by omitting the casting
- 49. 49 Lambdas
- 50. 50 Lambdas
- 51. 51 Streams
- 52. 52 What is a stream and what not? § It is a pipeline of functions that can be evaluated. § They are not a data structure. § They can transform data – but cannot mutate them.
- 55. 55 Streams and Lambdas Much cleaner implementation using Streams and Lambdas Obey the new lines – better for debugging...
- 56. 56 Streams – a little bit more complete Output: C1 C2
- 57. 57 Streams – a little bit more complete Source:http://zeroturnaround.com/rebellabs/java-8-streams-cheat-sheet/attachment/java-8- streams-cheat-sheet-v3/
- 58. 58 Date and Time
- 59. 59 Date and Time § Who loves Date and Time operations in Java? § Who is using Joda Time?
- 60. 60 Date and Time – Spot the error +1900 0-based
- 61. 61 Date and Time – Basic Concept § LocalDate, LocalTime, LocalDateTime § Instant (amount of time since the epoch, i. e. for timestamps) § Period § Duration
- 62. 62 Date and Time – Examples § Now -> LocalDate.now() § Static -> LocalDate(2013, Month.JANUARY, 21) § Parse -> LocalDate.parse() § Conversion -> Calendar.getInstance().toInstant()
- 63. 63 Date and Time – Examples
- 64. 64 Date and Time – Examples
- 65. 65 Q & A!