Perspective about Java/JDK8 from a .Net developer

[Ciprian Khlud]

Hi all,

Sorry for a rant like message but this is my perspective as I want to learn
Java at least for the sake of learning something else than the Windows/Mono
centric experience I have from my past.

Also forgive me for my grammar mistakes, I'm not native English speaker.

This is how I perceive Java as for now as a .Net developer (and C++) with
close of 10 years of programming (and some before in university & co).

I will start with the great points:
- Java Hot-Spot optimizer gives right numbers in benchmarks! Even more, I
was really impressed with it
- JDK 8 is a GREAT step forward as for me: reading all lines from a file is
provided eventually by the JDK, or read all string without Buffered kind of
classes
- JavaFX feels and runs great! I was expecting to have glitches and I never
seen one in my tutorial like experiments at least! Really good job here!
- HotSpot defaults are great (with Tiered compilation)

Right now the not so great:
- Java language looks primitive, and even as Lambda is definitely a step in
the right direction. Code simplification should be done for the sake of
language simplification. I don't have anything to promote, but after a week
of Java, I eventually switched to Kotlin. I don't want to say that Kotlin
is the answer, I understand that Scala is also praised
- JVM startup is horrible, especially when you run multiple tools like
running an unit test. A simple list with Kotlin (in IDE) against JDK8 runs
in 40 seconds in my laptop. I understood that this is the "worst case" as
many tools start, do a little work (like kotlin compiler) and after that
stops and another tool starts, and so on! I understand, but I can say in a
similar use-case in the .Net world takes like 2-3 seconds, maybe 5 seconds.
I've been told that Jigsaw will fix (mostly) this and it will be part of
Java 9. I hope it does, I downloaded JDK9 but my simple app crashes (and
I'm not sure if it does support Jigsaw).
- I heard about Maven but maybe I don't understand how to use it, but for a
simple project I eventually copied jars from another project. This is
certainly a proof of my incompetence, but I want to say that in VS like
tools you have access to the NuGet somewhat seamless. Maybe NetBeans (or
Idea) have this integration, but was not obvious as: "add Reference" ->
"online" -> "search JUnit"
- I heard that in future "struct" type will be supported. I hope it does! I
found that Java is using a bit too much memory for my taste and I have to
make my custom queue to support compact primitives. Honestly I liked more
the description of PackedObject, but this is a personal take. Maybe I'm
more interested in low overhead PInvokes than low-memory Java. Who knows,
maybe value types solve both. I am in the state of "wait and see". But as
for me the performance of platform calls would be a better spent time than
improving Java's good runtime performance, but maybe I'm wrong.

So as in conclusion: these views are mine and are based in the try to learn
how to make a JavaFx and OpenGl applications (I diched OpenGL as I did find
Jogl to be hard to work with, I'm trying LibGdx now, but I am doing just
the tutorial work) and trying to make a simple (snake kind) game.

For the sake of comparison, all my (home) work is done in opensource
manner. You can find the Java (NetBeans) and Kotlin projects (IntelliJ)
here: https://github.com/ciplogic
(skip it as a seasoned Java developer, my point is simply to say that these
were my experiements).

So as lessions from the .Net world to Java (living mostly in a desktop
centric world):
+ great runtime performange (after warmup).
+ great JavaFx (kudos once again for the team)
+ simplifying language in JDK8 is a great choice
- slow startup (is it very bad when your final development is just invoking
small tools up to the point of your final code, making hotSpot to not warm
up enough. Probably Jigsaw can fix this.
- Maven (!?) integration maybe inside popular IDEs to have a unified way to
do stuff (!? - maybe it has)

Thank you for reading all and if there are any resources I forgot to
follow, I would be glad to see any resources maybe from a migration
standpoint.

Regards and thank you,
Ciprian