Those are the slides for my presentation at OracleCode One 2018. Java is moving faster and faster. A lot of features are not as known as they should be. Let's review together the ones I think you've missed in old versions. Then I will kickstart you on 9, 10 and 11 features that you never had time to look at.

1. © Henri Tremblay 2015
Henri Tremblay
Senior Software Engineer
Terracotta, a Software AG company
Java 5,6,7,8,9,10,11: What did you miss?
[TUT4828]
@henri_tremblay

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Henri Tremblay

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Henri Tremblay

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Henri Tremblay
• More or less made possible class mocking and proxying
• Coined the term “partial mocking”

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Henri Tremblay
• More or less made possible class mocking and proxying
• Coined the term “partial mocking”

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5
11
Good old
New & shinny

8. 8
8 minutes break (please do come back)

9. 9
Show of hands

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You voting for me

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Questions

12. 12
Java Delivery Process

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Java 6 Java 7 Java 8
Old delivery process
5 years 3 years 3 years

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Java 9 Java 10 Java 11
New delivery process
6 months 6 months 6 months

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2006 20142007 2008 2009 2010 2011 2012 2013 20202015 2016 2017 2018 2019 2021 2022 2023 2024 2025 2026
Java 6 (last from Sun)
Java 7
Java 8 (LTS)
Java 5
Java 9
Java 10
Java 13
Java 12
Java 11 (LTS)

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TL;DR
OracleJDK: Free and supported to 6 months
LTS versions have extended ($$$) support by Oracle
Identical to OpenJDK when free
OpenJDK: Free forever, not supported after 6 months
Built by https://adoptopenjdk.net/
Other JVMs (Azul, IBM, RedHat, etc.)
Supported by their vendor as they wish
A lot of “May” and “Possibly” in the party line
https://medium.com/@javachampions/java-is-still-free-
c02aef8c9e04

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Funny fact
Java 9 è Java 17.9
Java 10 è Java 18.3
Java 11 è Java 18.9
java version "11-ea" 2018-09-25
Java(TM) SE Runtime Environment 18.9 (build 11-ea+26)
Java HotSpot(TM) 64-Bit Server VM 18.9 (build 11-ea+26, mixed mode)

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17.9 18.3 18.9 19.3 19.9 20.3 20.9 21.3 21.9 22.3 22.9 23.3 23.9 24.3 24.9 25.3 25.9
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25

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@Deprecated
is back
Stronger than ever

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/**
* Counts the number of stack frames in this thread. The thread must
* be suspended.
*
* @return the number of stack frames in this thread.
* @throws IllegalThreadStateException if this thread is not
* suspended.
* @deprecated The definition of this call depends on {@link #suspend},
* which is deprecated. Further, the results of this call
* were never well-defined.
* This method is subject to removal in a future version of Java SE.
* @see StackWalker
*/
@Deprecated(since="1.2", forRemoval=true)
public native int countStackFrames();

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Java 1.1
(1997)

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Mustache instantiation
Hashtable map = new Hashtable() {{
put("key", "value");
}};

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Modern mustache instantiation
Map<String, String> map = new HashMap<>() {{
put("key", "value");
}};

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Modern map instantiation (Java 9)
Map<String, String> map =
Map.of("key", "value");

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Slightly longer map instantiation
private Map<String, String> map = new HashMap<>();
{
map.put("key", "value");
}

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Java 5
(2004)

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JAVA 5 GAVE THE GENERIC
TYPES TO THE WORLD
(and also annotations, concurrent collections, enum types, for
each, static imports and so on and so on)

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Type witness
MyClass.<List<String>> anyObject()
because you can’t
(List<String>) MyClass.anyObject()

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Type witness
MyClass.<List<String>> anyObject()
because you can’t
(List<String>) MyClass.anyObject()

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Java 6
(2006, last from Sun)

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JAVA 6 BROUGHT.. PRETTY
MUCH NOTHING
(a bunch of performance improvements under the hood, better xml
parsing and the first scripting api)

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Java 7
(2011, first from Oracle)

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JAVA 7 BROUGHT A LOT OF
SYNTACTIC SUGAR
(plus invokeDynamic, forkJoin, better file IO)

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Switch for strings
switch(s) {
case "hello":
return "world";
case "bonjour":
return "le monde";
}

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Diamond operator
List<String> list = new ArrayList<>();

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Binary integer literals and underscores
int i = 0b1110001111;
int i = 1_000_000;

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Multiple catches
try {
// ... do stuff
}
catch (IOException | SerializationException e) {
log.error("My error", e);
}
Instead of
try {
// ... do stuff
} catch (IOException e) {
log.error("My error", e);
} catch (SerializationException e) {
log.error("My error", e);
}

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Auto Closeable
Before
InputStream in = new FileInputStream("allo.txt");
try {
// … do stuff
} finally {
try { in.close(); } catch(IOException e) {}
}
After
try(InputStream in = new FileInputStream("allo.txt")) {
// … do stuff
}

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Auto Closeable
Real code you should do
InputStream in = new FileInputStream("allo.txt");
try {
// … do stuff
in.close();
} catch(IOException e) {
try {
in.close();
} catch(IOException e1) {
e.addSuppressed(e1);
}
throw e;
}

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File IO API
List<String> lines =
Files.readAllLines(
Paths.get("path", "to", "my", "file.txt"));
// also: file watcher, symbolic links, file locks,
// copy … Look in java.nio.file

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Java 8
(2014)

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JAVA 8: LAMBDA!
(and also a new date API, default methods, metaspace, Nashorn,
JavaFX and CompletableFuture)

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Base64 ;-)
import java.nio.charset.StandardCharsets;
import java.util.Base64;
public class Base64s {
public static void main(String[] args) {
final String text = "Base64 finally in Java 8!";
final String encoded = Base64
.getEncoder()
.encodeToString( text.getBytes( StandardCharsets.UTF_8 ) );
System.out.println( encoded );
final String decoded = new String(
Base64.getDecoder().decode( encoded ),
StandardCharsets.UTF_8 );
System.out.println( decoded );
}
}

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Date / Time API
Core ideas:
Immutable
A time is a time, a date is a date. Not always both (like java.util.Date)
Not everyone uses the same calendar (the same Chronology)
LocalDate, LocalTime, LocalDateTime à Local. No time zone
OffsetDateTime, OffsetTime à Time with an offset from
Greenwich
ZonedDateTime à LocalDateTime with a time zone
Duration, Period à Time span
Instant à Timestamp
Formatting à Easy and thread-safe formatting

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Date / Time API (example)
LocalDateTime now = LocalDateTime.now();
String thatSpecialDay = now
.withDayOfMonth(1)
.atZone(ZoneId.of("Europe/Paris"))
.plus(Duration.ofDays(5))
.format(DateTimeFormatter.ISO_ZONED_DATE_TIME);
System.out.println(thatSpecialDay);
Output
2016-09-06T17:45:22.488+01:00[Europe/Paris]

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Lambda: 11th letter of the Greek alphabet

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(also written as λ-calculus) is a formal system in
mathematical logic for expressing computation based
on function abstraction and application using variable
binding and substitution. It is a universal model of
computation that can be used to simulate any single-
taped Turing machine and was first introduced by
mathematician Alonzo Church in the 1930s as part of an
investigation into the foundations of mathematics.
Lambda calculus

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This is a function:
This is a lambda:
Lambda calculus

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c = coll.forEach(
(a, b) –> pow(a, 2) + pow(b, 2)
)
Functional programming

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Lambda
// Classic
list.forEach(e -> System.out.println(e));
// Typed
list.forEach((String e) -> System.out.println(e));
// Multiline
list.forEach((String e) -> {
System.out.println(e);
});
// With closure
String greeting= "Hello ”;
list.forEach(e -> System.out.println(greeting + e));

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Implicit final
List<String> list = new ArrayList<>();
String greeting = "Hello "; // no final required
list.forEach(s -> System.out.println(greeting + s));
list.forEach(new Consumer<String>() {
@Override public void accept(String s) {
System.out.println(greeting + s);
}
});
list.forEach(s -> greeting = “Hi”); // won’t compile

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Interface default methods
public interface List<E> extends
Collection<E> {
default void replaceAll(UnaryOperator<E>
operator) {
// …
}
}
public interface A {
default void foo() { }
}
public interface B{
default void foo() { }
}
public class C implements A, B {} // forbidden
public class C implements A, B { // allowed
public void foo() { }
}
public static class D implements A, B { //
allowed
public void foo() {
A.super.foo();
}
}

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Interface static methods
public interface IntStream {
static IntStream empty () {
return …;
}
}
IntStream stream = IntStream.empty ();

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Mustache vol. 2
Map<Long, Person> persons = Map.of(
1L, new Person(12, "Marc"),
2L, new Person(58, "Pierre”)
);
persons.entrySet().stream()
.map(entry -> new Object() {
long id = entry.getKey();
String name = entry.getValue().getName();
})
.forEach(tuple -> {
System.out.println(tuple.id + ": " + tuple.name);
});
}

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Everything is a lambda
public interface MyInterface {
int foo();
}
public void bar(MyInterface i) {
System.out.println(i.foo());
}
bar(() -> 4);
bar(new MyInterface() {
@Override public int foo() {
return 4;
}
});
JButton btn = new JButton();
btn.addActionListener(e -> {});
But it’s better to flag them
with
@FunctionalInterface

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Method references
public static class Passenger {
public void inboard(Train train) {
System.out.println("Inboard " + train);
}
}
public static class Train {
public static Train create(Supplier< Train > supplier)
{
return supplier.get();
}
public static void paintBlue(Train train) {
System.out.println("Painted blue " + train);
}
public void repair() {
System.out.println( "Repaired " + this);
}
}
Train train = Train.create(Train::new); // constructor
List<Train> trains = Arrays.asList(train);
trains.forEach(Train::paintBlue); // static
method
trains.forEach(Train::repair); // instance
method
Passenger p = new Passenger();
trains.forEach(p::inboard); // instance
method taking this in param
trains.forEach(System.out::println); // useful!

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Upside Down
public class MethodTest {
public class Foo {
static final String ERR_MESSAGE = "bad";
public void doIt() throws IllegalStateException {
throw new IllegalStateException(ERR_MESSAGE);
}
}
@Test
public void test() {
Foo foo = new Foo();
Throwable t = captureThrowable(foo::doIt);
assertThat(t)
.isInstanceOf(IllegalStateException.class)
.hasMessage(Foo.ERR_MESSAGE);
}
public static Throwable captureThrowable(Runnable r) {
Throwable result = null;

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Streams
try(Stream<String> lines =
Files.lines(Paths.get("src/Streams.java"))) {
System.out.println(lines.findFirst());
}

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Functional programming
List<String> list = new ArrayList<>();
int sum= list
.stream()
.filter(s -> s.startsWith("a"))
.mapToInt(String::length)
.sum();
List<Integer> length = list
.stream()
.map(String::length)
.collect(Collectors.toList());

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Parallel
List<String> list = new ArrayList<>();
int sum = list
.parallelStream()
.filter(s -> s.startsWith("a"))
.mapToInt(String::length)
.sum();
Arrays.parallelSort(array);

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Optional
try(Stream<String> lines =
Files.lines(Paths.get("src/Streams.java"))) {
System.out.println(lines.findFirst());
}
è Optional[import java.io.IOException;]
Optional<String> findFirst();
Solution: lines.findFirst().get();
èimport java.io.IOException;

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Java 9
(2017)

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JAVA 9: MODULES!
(and G1 by default, var handles, new http client, jshell, jcmd,
immutable collections, unified JVM logging)

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Improved try-with-resource
ByteArrayOutputStream in = new ByteArrayOutputStream();
try(in) {
}

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Java 10
(March 2018)

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JAVA 10: VAR
(application class-data sharing, GraalVM)

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Keywords
while, if, abstract, public, default,
class, enum (Java 5), _ (Java 9)
Restricted Keywords
open, module, to, with
Literals
true, false, null
Reserved identifier
var
What is var?

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Java 11
(September 2018)

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JAVA 11: CLEANUP
(and dynamic class-file constants, epsilon, java.xml, corba and
many J2EE modules removed, nashorn removed, ZGC, single file
program)

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Prepare to do some stretching
Java 8 Java 9 Java 10 Java 11
What any sane person will want his/her framework to support

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Prepare to do some stretching
Java 8 Java 9 Java 10 Java 11
What any sane person will want his/her framework to support
Unsafe.defineClass()
MethodHandles.defineClass()
Unsafe.defineClass()
removed

72. 72
Prepare to do some stretching
Java 8 Java 9 Java 10 Java 11
What any sane person will want his/her framework to support
import java.xml.bind
--add-modules javax.xml.bind
--module-path containing
jaxb-api-2.4.0-xxx.jar

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The End

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Who has learned
something today?
?

75. 75
Java Champions – Java is still free
https://medium.com/@javachampions/java-is-still-free-c02aef8c9e04
Adopt OpenJDK
https://adoptopenjdk.net/
Maurice Naftalin’s Lambda FAQ
http://www.lambdafaq.org/
Zeroturnaround Module Cheat Sheet
http://files.zeroturnaround.com/pdf/RebelLabs-Java-9-modules-cheat-sheet.pdf
Var styleguide
http://openjdk.java.net/projects/amber/LVTIstyle.html
Heinz Kabutz’s online course
https://javaspecialists.teachable.com/courses
Links

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Modern Java in Action
Raoul-Gabriel Urma and Mario Fusco
Mastering Lambdas
Maurice Naftalin
Java 9 Modularity
Sander Mak and Paul Bakker
Books

77. 77
Caching in Applications still matters
[DEV5935]
Henri Tremblay & Anthony Dahanne
Moscone West – Room 2007
Next talk

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You voting for me

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Questions? http://montreal-jug.org
? http://easymock.org
http://objenesis.org
http:/ehcache.org
Henri Tremblay
http://blog.tremblay.pro
@henri_tremblay