Java is dead, long live Scala, Kotlin, Ceylon, etc.

Copyright © 2014 Russel Winder 1
Java is Dead
Long Live Scala, Kotlin, Ceylon,
etc.
Russel Winder
email: russel@winder.org.uk
twitter: @russel_winder
Web: http://www.russel.org.uk

Java is Dead

Java is Dying

What are the symptoms?
● Java is seriously verbose.
● Java has poor type inference.
● Java has only low-level support for concurrency and
parallelism.
● Java generates a dependency hell .“ ”
● Java is a 1990s imperative language that isn't really
object-oriented.
● …

Is there a cure?
● Can Java:
● Be less verbose.
● Have better type inferencing.
● Do concurrency and parallelism better. (Doug Lea, Brian
Goetz and others have actually been doing this for a
while.)
● Have a reasonable module system, cf. Jigsaw vs. OSGi.
● Be a real object-oriented language.

Prognosis: not great

Alternatives?

Create a new language
● Java is a statically
typed, compiled
language, so create a
new statically typed
compiled language:
● Scala
● Kotlin
● Ceylon
● Fantom
● Gosu
● ?

Gross oversimplifications…

Scala
● Integrates functional
and object-oriented.
● Very declarative style
of expression.
● Strong support for data
parallelism. Also Akka
for actors and such-like.
● Strong static type
checking with
inferencing and reified
generic type
parameters.

Kotlin
● Top-level functions.
● Object-oriented, with
functional elements
● Strong static type
checking with
inferencing.
● Has modules.
● Allows extension
methods.
● Compiles to JavaScript
or JVM to support
end-to-end Web
applications
development.

Ceylon
● Object oriented with
functional features.
● Strong static typing
with inference.
● Explicit module
system.
● JavaScript and JVM
backends so as to be
end-to-end for Web
applications
development.

Fantom
● Object-oriented.
● Integrated modules
system via pods.
● Targets JVM and CLR.

Gosu
● Object-oriented.
● Scripts.

?
The identity of this statically typed, object-oriented
(with functional bits) language for the JVM will
remain unnamed at this time to preserve the air
of mystery and suspense.

Code!



What is the value of ?

Well that's easy, it's…



Obviously.

It's simples
Александр Орлов 2009

Approximating 
● What is it's value represented as a floating
point number?
● We can only obtain an approximation.
● A plethora of possible algorithms to choose from, a
popular one is to employ the following integral
equation.
π
4
=∫0
1 1
1+x2
dx

One possible algorithm
● Use quadrature to estimate the value of the
integral which is the area under the curve.–
π=
4
n
∑i=1
n 1
1+(
i−0.5
n
)
2
With n = 3 not much to do,
but potentially lots of error.
Use n = 107
or n = 109
?
Embarrassingly
parallel.

Because addition is commutative and
associative, expression can be
decomposed into sums of partial sums.

a + b + c + d + e + f
=
( a + b ) + ( c + d ) + ( e + f )

Scatter Gather—
map reduce
data parallel

Code!

Scala
Kotlin
Ceylon

?

Surprise time…

JVM is a Groovy place

Groovy
● Object-oriented with
functional features.
● Extension methods.
● Compiles to JVM bytes
codes or JavaScript,
cf. GrooScript.
● Runs on Android.
● Scripts.
● A dynamic language
with a run time
meta-object protocol.

Groovy
A statically typed,
compiled language.

@TypeChecked
@CompileStatic

Groovy
● @TypeChecked:
● Traditional dynamic
Groovy but with full
static (compile-time)
type checking.
● @CompileStatic:
● Full static typechecked,
compilation to bytecode
at compile time.
● No dynamic meta-
object protocol.

Code!

Did I mention invokedynamic?

Code!

Java is Dead!

Groovy
(or Scala, Kotlin, Ceylon, Fantom, )…
is the future of static languages
on the JVM.

2014-03-18

Java 8
Released

Java 8 is the biggest revolution
in Java since 1994.
Bigger than Java 5.

Has Java revived?
Is this a new lease of life?

What's Interesting in Java 8?
● G1 garbage collector.
● Nashorn.
● JavaFX.
● Lambda expressions.
● Default methods in
interfaces (traits).
● Enhanced collections.
● Method references.

G1 garbage collector is now the
standard: no more PermGen.

Nashorn comes as standard:
Server-side JavaScript without Rhino.

JavaFX in the distribution:
you will want to use GroovyFX though.

Lambda expressions,
default methods in interfaces,
associated collections enhancements.

Code!

Java is Dead
Long Live Scala, Kotlin, Ceylon,
etc.
Russel Winder

Java is Dead
Long Live Java
Russel Winder

Java is Dead
Long Live Groovy
Russel Winder

Java is dead, long live Scala, Kotlin, Ceylon, etc.

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Java is dead, long live Scala, Kotlin, Ceylon, etc.