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

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Copyright © 2014 Russel Winder 4 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. ● …

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Copyright © 2014 Russel Winder 5 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.

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Copyright © 2014 Russel Winder 8 Create a new language ● Java is a statically typed, compiled language, so create a new statically typed compiled language: ● Scala ● Kotlin ● Ceylon ● Fantom ● Gosu ● ?

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Copyright © 2014 Russel Winder 10 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.

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Copyright © 2014 Russel Winder 11 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.

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Copyright © 2014 Russel Winder 12 Ceylon ● Top-level functions. ● 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.

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Copyright © 2014 Russel Winder 15 ? 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.

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Copyright © 2014 Russel Winder 26 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

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Copyright © 2014 Russel Winder 27 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.

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Copyright © 2014 Russel Winder 36 Groovy ● Top-level functions. ● 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.

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Copyright © 2014 Russel Winder 39 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.

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Copyright © 2014 Russel Winder 51 What's Interesting in Java 8? ● G1 garbage collector. ● Nashorn. ● JavaFX. ● Lambda expressions. ● Default methods in interfaces (traits). ● Enhanced collections. ● Method references.