Re: [Caml-list] Invoking Java programs from an OCaml program

[Sebastien Ferre <Sebastien.Ferre@irisa.fr>]

Hi,

I have used camljava in one project. I found
that solution satisfying although it does involve
a lot of boilerplates, indeed. It makes it possible
to use a JAR a bit like a C library. At runtime, it
is sufficient to set the CLASSPATH.

If you are curious, visit http://www.irisa.fr/LIS/softwares/pew/
from where you can find the source code, and execution instructions.
(boilerplate code is in file owlapi.ml)

I am interested by solutions to ease the generation of
boilerplates.

Best,
Sébastien Ferré

On 12/18/2015 11:25 AM, Seungcheol Jung wrote:
> Hi, list.
>
> I am also looking for a way to use Java library in OCaml application. My
> OCaml
> application is performance-critical static source code analyzer. I found two
> options: X. Clerc's OCaml-Java and X. Leroy's camljava. Which one is more
> suitable?
>
> 1. OCaml-Java
>  From my understanding, OCaml-Java[1] compiles OCaml code into byte code and
> packs the byte code, interpreter, and Java code into one Java
> application. It
> looks more like embedding OCaml code in Java, not getting some help from
> Java. So it does not satisfy my pro-OCaml taste. I am also concerned about
> slowdowns due to byte code and interpreter.
>
> 2. camljava
> I think camljava[2] is more suitable for my purpose. Using camljava, I can
> launch JVM and call Java methods via JNI from native OCaml applications.
> However, it is a very low-level interface so that I need to implement many
> boilerplates by hand (O'Jacaré[3] might reduce some burden?) and beware of
> type-safety. Also, it is not maintained for a long time (the latest
> version came out before ten years ago).
>
> Do you have any suggestions? Moreover, could anyone share some real-world
> stories about OCaml-Java binding?
>
>
> Regards,
> Seungcheol Jung
>
> [1] http://www.ocamljava.org/
> [2] https://forge.ocamlcore.org/projects/camljava/
> [3] http://www.pps.univ-paris-diderot.fr/~henry/ojacare/index.en.html
>
>
> On 16 December 2015 at 22:29, Chan Ngo <chan.ngo2203@gmail.com
> <mailto:chan.ngo2203@gmail.com>> wrote:
>
>
>>     On Dec 15, 2015, at 6:21 AM, Paul Pelzl <pelzlpj@gmail.com
>>     <mailto:pelzlpj@gmail.com>> wrote:
>>
>>     On Mon, Dec 14, 2015 at 9:25 AM, Chan Ngo <chan.ngo2203@gmail.com
>>     <mailto:chan.ngo2203@gmail.com>> wrote:
>>
>>         An alternative, if you want to do as follows:
>>         - Compile Java program to an executable (not jar file)
>>         - Call this executable and get the return values from it
>>
>>         So you can think about Unix module in OCaml, you can use the
>>         standard I/O to realize a communication channel between your
>>         OCaml code and the executable Java.
>>         https://ocaml.github.io/ocamlunix/ocamlunix.html
>>
>>
>>     If the data to be exchanged is structurally complex, then this
>>     technique becomes difficult; a cross-platform serialization
>>     library can be very helpful for generating appropriate
>>     serialization code in multiple languages.  As one example, Cap'n
>>     Proto has bindings for both Java and OCaml:
>>     https://capnproto.org/otherlang.html
>
>     Yes, I agree, in some cases, it will become difficult and we need a
>     cross-platform serialization library. Your example is a good point.
>     In addition, if you can control the source code of the Java side,
>     you can modify the code such that it can return the result as JSON
>     object then the OCaml side can get this object value to parse
>     complex data structures.
>
>     Best,
>
>     ---
>     Chan Ngo
>     INRIA,
>     (+33)02 99 84 72 84 <tel:%28%2B33%2902%2099%2084%2072%2084>
>     chan.ngo@inria.fr <mailto:chan.ngo@inria.fr>
>     http://people.rennes.inria.fr/Chan.Ngo
>
>