This document summarizes Jeanne Boyarsky's presentation on Java 11. Some key points include: - Java releases are now every 6 months with smaller incremental updates, moving from a major version every 3 years to a faster release cycle. - Local variable type inference (var) was added in Java 10 for less boilerplate code. - Java 11 includes improvements to the HTTP client, garbage collection algorithms, and other minor features and bug fixes. - Time-based versioning provides more clarity around Java version numbers and their component parts.

1. @jeanneboyarsky
Java 11 – Keeping the Java Release
Train on the Right Track
speakerdeck.com/boyarsky
Jeanne Boyarsky
QCon– June 28, 2018

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java-10-11

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4. @jeanneboyarsky
So much
changed
since Java
9 & Jigsaw’s
release!
2

5. @jeanneboyarsky 3

6. @jeanneboyarsky
For more on Java 9, see:
https://speakerdeck.com/
boyarsky/welcome-to-
java-9?slide=1
4

7. @jeanneboyarsky
Topics:
• Ecosystem
changes
• Language
changes
5

8. @jeanneboyarsky
About Me
16 years as
Java Developer
6

9. @jeanneboyarsky
Memories!
7

10. @jeanneboyarsky
Til
Java 6
(1996-
2006)
Hi
Oracle
(2010)
Java 7
(2011)
Java 8
(2014)
Java 9
(2017)
8

11. @jeanneboyarsky
The Saga of Jigsaw
• 2011 – Maybe part of Java 7. Nope
Plan B
• 2012 - Part of Java 8. No wait
• 2014 - Part of Java 9
9

12. @jeanneboyarsky
Java 9 “Release” Dates
• Sept 2016
• May 2017
• July 2017
• Sept 2017
10

13. @jeanneboyarsky
Counting lessons?
• 1.0, 1.1, 1.2, 1.3, 1.4
• 5.0
• 6, 7, 8, 9, 10, 11
11

14. @jeanneboyarsky
Advanced counting lessons
• 10 = 2018.3
• 11 = 2018.9
• 12 = ?
12

15. @jeanneboyarsky
Wait, a major version every 6 months?
• + Syntax changes
• + Smaller features
• - Years of features
JDK 10 JDK 11
12 new
features
15 new
features
13

16. @jeanneboyarsky
Java School
Report Card
Developer
Community
 A
Features
 B
Frequency of
Release
 F
Predictability
of Release
 D
14

17. @jeanneboyarsky
JVM College
Report Card
Vocabulary
 B
Polyglot
programming
 A
Frequency of
Release
 F
Predictability
of Release
 D
15

18. @jeanneboyarsky
Re-org at
the train
station
16

19. @jeanneboyarsky
How many languages do you know?
 One (or zero)
 Two – Five
 Six or more
Examples
• Java
• Kotlin
• Groovy
• Scala
• SQL
• HTML
• JavaScript
• CSS
17

20. @jeanneboyarsky
Before Now
18

21. @jeanneboyarsky
Before Now
19

22. @jeanneboyarsky
Before Now
Releases
every
Varies 6 months
(or 3 years)
Releases are Feature
driven
Date driven
20

23. @jeanneboyarsky
More time to
code while I wait
for the next train!
21

24. @jeanneboyarsky
Arrivals Train Schedule
Java Release Date Long Term
Support
9 September 21, 2017
10 March 20, 2018
11 September 25, 2018
22

25. @jeanneboyarsky
Security Patches Departure Schedule
Java Public Patches Paid Patches
6 2013 Late 2018
7 2015 2022
8 January 2019 (business)
December 2020 (public)
2025
23

26. @jeanneboyarsky
Security Patches Departure Schedule
Java Public patches Paid patches
9 March 2018 n/a
10 September 2018 n/a
11 March 2019 2023-2028
24

27. @jeanneboyarsky
Wait. So what happens next?
How long will Java 12 have security patches?
Answer: 6 months
What is the next LTS version
after Java 11?
Java 11 + 3*2 = 17
25

28. @jeanneboyarsky
A Tale of Two JDKs
Java Oracle JDK Open JDK
New Version Every 3 years Every 6 months
Cost Paid Free
Upgrade Options • Security patch
• Next version
• OpenJDK
• Interim
security patch
• Next version
26

29. @jeanneboyarsky
Only bug fixes remain
Only bug fixes allowed
27

30. @jeanneboyarsky
Get ready to play
28

31. @jeanneboyarsky
Tip: Aliases
alias
javac11=/Library/Java/JavaVirtualMachines/jdk-
11.jdk/Contents/Home/bin/javac
alias
java11=/Library/Java/JavaVirtualMachines/jdk-
11.jdk/Contents/Home/bin/java
29

32. @jeanneboyarsky
LOCAL VARIABLE SYNTAX
(10/11)
30

33. @jeanneboyarsky
String name = "Jeanne”;
var name = "Jeanne";
List list = List.of(1, 2, 3);
var list = List.of(1, 2, 3);
• Syntactical sugar/less boilerplate
• Not immutable (no val)
(10)
31

34. @jeanneboyarsky
var name = "Jeanne";
String name2 = name;
• Compiled code same with var
(10)
32

35. @jeanneboyarsky
List<WebElement> headers =
thead.findElements(By.tagName("th"));
VolunteerDashboardRow headerRow = new
VolunteerDashboardRow(headers);
vs
var headers =
thead.findElements(By.tagName("th"));
var headerRow = new
VolunteerDashboardRow(headers);
(10)
33

36. @jeanneboyarsky
var csvPath = createAndGetFile(CSV_DATA);
try (var csvWriter =
Files.newBufferedWriter(csvPath);
var csvPrinter = new
CSVPrinter(csvWriter,
CSVFormat.DEFAULT)); {
}
(10)
34

37. @jeanneboyarsky
Map<Integer, String> productMap1
= new HashMap<Integer, String>();
Map<Integer, String> productMap2
= new HashMap<>();
var productMap3
= new HashMap<Integer, String>();
(10)
35

38. @jeanneboyarsky
Where can we use?
var name = "Jeanne";
var other = name + 2;
var list = List.of(1, 2, 3);
for (var num : list) {}
(10)
36

39. @jeanneboyarsky
Where can’t we use?
class Inner { var bad = "abc"; }
var noGood;
noGood = 4;
• Also instance variables, etc
(10)
37

40. @jeanneboyarsky
Does this work?
var var = "var";
(10)
38

41. @jeanneboyarsky
(10)
Pros Cons
Less typing Loss of information
Less redundancy Variable names matter
more
Can scan variable
names
Be careful!
39
http://openjdk.java.net/projects/amber/LVTIstyle.html

42. @jeanneboyarsky
Lambdas
Predicate<String> pred1
= p -> true;
Predicate<String> pred2
= (String p) -> true;
Predicate<String> pred3
= (var p) -> true;
(11)
40

43. @jeanneboyarsky
Annotations
BiPredicate<
Map<Integer, String>,
List<String>> func =
(@NotNull var map, var list) -> true;
(11)
41

44. @jeanneboyarsky
All or nothing
Good
(var map, var list) -> true
No good
(var map, list) -> true
(var map, List list) -> true
(11)
42

45. @jeanneboyarsky
GARBAGE COLLECTION
(10/11)
43

46. @jeanneboyarsky
Choose your own GC
• Who cares?
• Agile. With releases every 6 months, features
are smaller
(10)
44

47. @jeanneboyarsky
Faster Default GC
Java 8 Parallel Garbage
Collector
Java 9 G1 GC
Java 10 + 11 G1 GC with parallel
implementation
(10)
For more, see https://speakerdeck.com/cguntur/garbage-
collection-in-java-9
45

48. @jeanneboyarsky
Regions & space vs speed
(10)
For more, see https://speakerdeck.com/cguntur
46

49. @jeanneboyarsky
Epsilon GC
(11)
• Never reclaims memory
• Program proceeds until run out of heap
• GC never runs
• To use:
• -XX:+UseEpsilonGC
• (or) -XX:+UseNoGC
47

50. @jeanneboyarsky
Epsilon GC Good for
(11)
• Performance/memory stress test
• Very short programs
• Last ditch performance improvements
(this probably isn’t you)
48

51. @jeanneboyarsky
Z GC
(11)
• Experimental
• 10ms or less pause time
• Only for Linux/x64
• To use, enable both:
• -XX:+UnlockExperimentalVMOptions
• -XX:+UseZGC
49

52. @jeanneboyarsky
HTTP CLIENT
(11)
I’m done
incubating!
50

53. @jeanneboyarsky
(11)var uri = "http://www.google.com";
var client = HttpClient.newHttpClient();
var request = HttpRequest.newBuilder()
.uri(URI.create(uri))
.build();
var response = client.send(request,
BodyHandlers.ofString());
System.out.println(response.body());
51

54. @jeanneboyarsky
(11)var client = HttpClient.newHttpClient();
var requests = uris.stream()
.map(HttpRequest::newBuilder)
.map(reqBuilder -> reqBuilder.build())
.collect(toList());
CompletableFuture.allOf(requests.stream()
.map(r->client.sendAsync(r, ofString()))
.toArray(CompletableFuture<?>[]::new))
.join();
52

55. @jeanneboyarsky
Other APIs
• BodyHandlers – file, inputstream, string,
discarding
• Request Builder Options – Header, proxy,
authenticator, http protocol version
• Methods – get/post/put/delete
(11)
53

56. @jeanneboyarsky
TIME BASED VERSIONING
(10)
54

57. @jeanneboyarsky
String javaVersion =
System.getProperty("java.version");
Runtime.Version version =
Runtime.Version.parse(javaVersion);
System.out.println(javaVersion + ": "
+ version.feature() + " "
+ version.interim() + " "
+ version.update() + " "
+ version.patch());
(10)
55

58. @jeanneboyarsky
(10)
10.0.1 11-ea
[deprecated]
major()
10 11
[deprecated]
minor()
0 0
[deprecated]
security()
1 0
56

59. @jeanneboyarsky
(10)
10.0.1 11-ea
feature() 10 11
interim() 0 0
update() 1 0
patch() 0 0
57

60. @jeanneboyarsky
(10)
Updates Examples
feature() Every 6 months 10, 11, 12
interim() n/a for Open JDK 0
update() Within 6 months 0, 1, 2
patch() Emergencies 0, 1, 2
58

61. @jeanneboyarsky
System.out.println(
System.getProperty("java.version.date"));
(10)
10.0.1 11-ea
2018-04-17 2018-09-25
Yes, the future!
59

62. @jeanneboyarsky
System.out.println(
System.getProperty("java.version.version"));
• Null for Open JDK
• For vendor use
(10)
Yes, version is
here twice!
60

63. @jeanneboyarsky
ODDS AND ENDS
61

64. @jeanneboyarsky
New java launcher mode
Full command Shorthand
javac HelloWorld.java
java HelloWorld
java HelloWorld.java
Produces class file Fully in memory
For any program For programs with one
class
(11)
62

65. @jeanneboyarsky
Unmodifiable Collections
(10)
63
Copying another Terminal operations
List.copyOf Collectors.toUnmodifiableList
Set.copyOf Collectors.toUnmodifiableSet
Map.copyOf Collectors.toUnmodifiableMap

66. @jeanneboyarsky
Behind the Scenes
• Nest based access control
• Remove hack for private access in nested
classes
• Pay off tech debt
(11)
64

67. @jeanneboyarsky
JDK Java EE/Corba Modules
Java 9 Java 11
(11)
65

68. @jeanneboyarsky
Pack200 Tools
Java 11 Use jlink to
compress packages
(11)
66

69. @jeanneboyarsky
Nashorn
Java 11 • Challenging to maintain
• Unclear adoption
• May be adopted
• Made it into Java 11
two days before cutoff
(11)
67

70. @jeanneboyarsky
Unicode 9 and 10 Support
Languages + emoji
(10+11)
68

71. @jeanneboyarsky
Tying it all together
(10+11)
69
import java.nio.charset.*;
public class Unicode {
public static void main(String... args) {
System.out.print("Have a uD83CuDF7A");
System.out.println(" or a uD83EuDD64");
}
}

72. @jeanneboyarsky
No need to be
puzzled.
Java 11 LTS
6 months
New features
Go tell your
manager/team to
be ready for
September!
70

73. @jeanneboyarsky 71

74. Watch the video with slide
synchronization on InfoQ.com!
https://www.infoq.com/presentations/
java-10-11