Presentation slides from ISDC2013 held on 16-mar-2013 http://www.siliconindia.com/events-overview/India--Software-Developer-Conference-Bangalore-ISDC_2013Blr.html

1. Why Java is Still
Important?
What is new in Java 8
S. Shyam Sundar
Architect

2. Agenda
1 Introduction
2 Why is Java still relevant
3 What is new in the Java 8 Language
4 What is new in the JVM
5 Q/A

3. The Java Platform
Source: http://www.tbray.org/ongoing/When/200x/2008/08/05/Annotated-OSCON-Keynote

4. Why is Java still relevant?

5. Why is Java still relevant? Popular
TIOBE Programming Language Index
http://www.tiobe.com/index.php/content/paperinfo/tpci/index.html

6. Why is Java still relevant? Popular
# of projects on
https://github.com/languages

7. Why is Java still relevant? Popular
# of questions by tags on
http://stackoverflow.com/tags

8. Why is Java still relevant? Popular
# of questions in stackoverflow.com
# of github projects
http://redmonk.com/sogrady/2013/02/28/language-rankings-1-13/

9. Why is Java still relevant? Batteries included

10. Why is Java still relevant? Android
Android constitutes >70% of the handheld market

11. Why is Java still relevant? JVM
BYOP – Bring your own Programming Language

12. Why is Java still relevant?
• A rich ecosystem of libraries, frameworks and tools
(batteries included)
• Android (mobile and handhelds)
• The JVM (WORA, support for other languages also)
• Massive installed base
• Still one of the most popular languages around for
enterprise development
• Open Source (Community JCP/JEP)
• Backed by some of the biggest technology companies
(IBM, Google, Apache, RedHat)

13. What is new in Java 8

14. What is new in Java 8
• The use of lambda expressions (closures,
Moore's Law, simplifying concurrent
programming)
• Method references
• Default methods (monkey patching? Not
really)
• New Time API (JSR 310) (age calculation
finally becomes a one liner!! )
System.out.println("age is " +
Period.between(LocalDate.of(1980, 1, 1), LocalDate.now()).getYears());

15. What is new in Java 8 - Lambda
FileFilter filter = new FileFilter() {
@Override
public boolean accept(File pathname) {
return pathname.getName().endsWith(".java");
}
}; for ( File f : new File(".")
for ( File f : .listFiles( x ->
new File(".").listFiles(filter) ) { x.getName().endsWith(".java")) ) {
System.out.println(f); System.out.println(f);
} }
$ java -version
java version "1.6.0_41"
Java(TM) SE Runtime Environment (build 1.6.0_41-b02-445-11M4107)
Java HotSpot(TM) 64-Bit Server VM (build 20.14-b01-445, mixed mode)
$ javac Test.java
$ java Test
./Test.java
./Test8.java
$ $J8_HOME/bin/java -version
java version "1.8.0-ea"
Java(TM) SE Runtime Environment (build 1.8.0-ea-b79)
Java HotSpot(TM) 64-Bit Server VM (build 25.0-b20, mixed mode)
$ $J8_HOME/bin/javac Test8.java
$ $J8_HOME/bin/java Test8
./Test.java
./Test8.java

16. What is new in Java 8 – Method references
class Person { List<Person> people = Arrays.asList(
private final String name; new Person(20, "Jack"),
private final int age; new Person(42, "Bill"),
new Person(22, "Jill")
Person(int a, String n) { );
name = n; Collections.sort(people,
age = a; Person::compareByAge);
} System.out.println(people);
public static int compareByAge( Collections.sort(people,
Person a, Person b) { Person::compareByName);
return a.age - b.age; System.out.println(people);
}
public static int compareByName(
Person a, Person b) { $ $J8_HOME/bin/javac MethodRef.java
return a.name.compareTo(b.name); $ $J8_HOME/bin/java MethodRef
} [Jack age 20, Jill age 22, Bill age 42]
@Override [Bill age 42, Jack age 20, Jill age 22]
public String toString() {
return name + " age " + age;
}
}

17. What is new in Java 8 – Default methods
interface Shape { interface Shape {
double getWidth(); double getWidth();
double getHeight(); double getHeight();
} default double area() {
return getWidth() * getHeight();
class Rectangle implements Shape { }
}
double width, height;
Rectangle(double w, double h) {
width = w;
height = h; Default methods allow us
}
@Override
public double getWidth() {
specify default behaviour
}
return width; without having to introduce
abstract classes
@Override
public double getHeight() {
return height;
}
}

18. What is new in the JVM

19. What is new in JVM
• Convergence of the Hotspot and the JRockIt
• PermGen gives way to Metaspaces (JEP 122)
• Profiles ~ Java ME -> Java SE
• Reduce HotSpot’s class metadata memory
footprint
• More compact and efficient Nashorn Javascript
engine

20. Thank You