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engage 2016 - Get ready for moving from Java 6 to Java 8 - Now!
The document discusses the transition from Java 6 to Java 8, highlighting key improvements such as the introduction of switch statements for strings, the diamond operator for type inference, and enhanced automated resource management with the autocloseable interface. It further covers new features in Java 7 and 8, including lambda expressions, stream processing, and updates to date and time handling, aimed at improving code readability and reducing boilerplate. The presentation emphasizes the importance of adapting to these changes to leverage the benefits of newer Java versions.
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engage 2016 - Get ready for moving from Java 6 to Java 8 - Now!
- 1. 1 Get ready formoving 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 – ICAN!
- 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?
- 5.
- 6. 6 A timeline perspective Java6 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 sessioncovers § Switch-strings § Diamonds § Paths § Lambdas § Streams § Date/Time
- 8.
- 9. 9 Goodbye if-then-elseif-elseif-elseif… forStrings Way in Java 6 and smaller to check for different String types
- 10. 10 Goodbye if-then-elseif-elseif-elseif… forStrings § 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… forStrings Now a clean way. Alternative could be to use Enums (also prior Java 7).
- 12. 12 Diamonds are developersbest friends
- 13. 13 Diamonds are developersbest 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 developersbest 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. ;-)
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- 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.
- 23. 23 Underscore me § You‘vetwo seconds to identify these numbers
- 24. 24 Underscore me § Thewith 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‘vetwo seconds to identify these numbers
- 26. 26 Underscore me § You‘vetwo seconds to identify these n_e_w numbers
- 27. 27 Catch me ifyou can
- 28. 28 Catch me ifyou can One catch per named exception
- 29. 29 Catch me ifyou can multi-catch has been introduced with Java 7
- 30.
- 31. 31 NIO.2 § The handlingof 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 § Thinkof 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 Initiatesthe 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 Holdsthe results of the monitored events Map of all found events
- 37.
- 38. 38 default § Changes inInterfaces always led to changes in the classes they used them § The new default constructor introduces „backward“ compatibility
- 39.
- 40. 40 Before Java 8 Addinga new Interface method Compilation error on all classes that implement the Interface
- 41. 41 With Java 8 Methodbody needed
- 42. 42 With Java 8 Callinga duplicate default method
- 43.
- 44. 44 Lambdas § One ofthe 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 toiterate Sequential, not parallel!
- 46. 46 Lambdas Anonymous methods to therescue but ... Have you spotted the forEach?
- 47. 47 Lambdas Calling the anonymous innermethod directly via a lambda call
- 48. 48 Lambdas Shorten it evenmore by omitting the casting
- 49.
- 50.
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- 52. 52 What is astream 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.
- 53.
- 54.
- 55. 55 Streams and Lambdas Muchcleaner implementation using Streams and Lambdas Obey the new lines – better for debugging...
- 56. 56 Streams – alittle bit more complete Output: C1 C2
- 57. 57 Streams – alittle bit more complete Source:http://zeroturnaround.com/rebellabs/java-8-streams-cheat-sheet/attachment/java-8- streams-cheat-sheet-v3/
- 58.
- 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.