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

Copyright © 2014 Russel Winder 1

Java is DeadLong Live Scala, Kotlin, Ceylon,

etc.

Russel Winder

email: [email protected]: @russel_winder

Web: http://www.russel.org.uk

mailto:[email protected]


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.

π4=∫0

1 1

1+ x2dx


One possible algorithm

● Use quadrature to estimate the value of the integral which is the area under the curve.–

π=4n∑i=1

n 1

1+(i−0.5n

)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 andassociative, 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!


ScalaKotlinCeylon


?


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!



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 8Released


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!



Code!


Java is DeadLong Live Scala, Kotlin, Ceylon,

etc.

Russel Winder





Java is DeadLong Live Java

Russel Winder





Java is DeadLong Live Groovy

Russel Winder




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