The myth of using Scala as a better Java

Re:The myth of using Scala as a better Java by sreque on Thursday March 02, 2017 @02:17PM (#13777246)

You asked for examples and that proceeded to defend almost all of the ones I listed, which basically proves my point that this is how things work in the Java community.

You can call things via reflection, therefore the language is dynamic? You have a strange definition of what makes a language dynamic. By that definition just about every language is dynamic. In C/C++ I can dynamically load symbols, call functions by string names, call C++ constructor functions, etc.

I've never in practice seen anyone use compile-time annotation processors. In practice, annotations define runtime global variables that some frameworks make use of by doing expensive classpath scanning on startup to add or rewrite bytecode at runtime. These frameworks basically help cement java's reputation for having incredibly slow startup times while at the same time making it very difficult to understand how your code works. Even if you aren't doing classpath scanning to generate code, using annotations also introduces unnecessary coupling in your code in practice. The blog post will have some good examples I've seen in the wild. :)

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Re:The myth of using Scala as a better Java by agentgt on Thursday March 02, 2017 @02:29PM (#13777362)

> In practice, annotations define runtime global variables that other frameworks can make use of by doing expensive classpath scanning on startup to rewrite bytecode at runtime.

Dagger2 is DI a compile time annotation library. Yes there needs to be a lot more libraries like this.

I totally understand some of your hate for annotations (I have my own with Spring Boot).

Despite my tone from the previous comment I think there should be a lot more plain old programmatic configuration (ie just load up objects and setup some properties during the bootstrap).

I had aspirations of making a howto guide using Dagger2 and various other compile time / code generation libraries (like jOOQ and MapStruct) as I too absolutely hate the classpath scanning hell that is Spring these days.

I can't deny though that some people find the "magic" more productive particularly for ramp up time.

All in all I violently agree with you more than you think (hence why I'm looking forward to your post).

I still don't know what a dynamic language is and neither does Wikipedia for that matter [1]. Its pretty nebulous. Its like saying strongly typed.

[1]: https://en.wikipedia.org/wiki/Dynamic_programming_language#E...

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Re:The myth of using Scala as a better Java by NiceGuy_Ty on Friday March 03, 2017 @09:59AM (#13783241)

Dynamically typed languages carry the types of values at runtime. That is, whatever is executing your code can look at a value itself and read off the type of it. Statically typed languages check all of the types of their values at compile time to make sure that it's sound. Then, they can strip the type information from those values and execute them without having to perform any runtime checks. In a dynamically typed language, the way to apply an operation is to read the type tag on it first, make sure the operation you want to apply can be applied to it, and then execute that operation. In a statically typed language, that check happened at compile time, so you're safe to just apply the operation to the value. Oftentimes languages may not be fully statically typed or fully dynamically typed. Java's use of reflection, instanceof, and casting means that it carries some type information at runtime. C++ has typid, C# has GetType(), etc. etc. Haskell as a language has full type erasure and can be considered fully statically typed, but there are some. GHC extensions (Typeable) which point to some type information being held at runtime by the compiler.

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