You can keep things in separate projects without having to copy the .class files to the Python project provided that you make that project a PyDev project and add the place that contains the .class files (i.e.: bin folder) as a source folder in the PyDev configuration (and reference that project from your Python project).
Take a look at "Project reference for Jython users" (in the end of http://pydev.org/manual_101_project_conf2.html).
I think you could also do what you asked in your question: create a java project, set it as a PyDev project too (right click that project > pydev > set as pydev project) and configure the PyDev project properties setting the PYTHONPATH to the place where you have your Python files and add another entry to the bin folder (i.e.: where the .class files exist). Not sure if it'd be better to keep those as 2 separated projects though.
You can keep things in separate projects without having to copy the .class files to the Python project provided that you make that project a PyDev project and add the place that contains the .class files (i.e.: bin folder) as a source folder in the PyDev configuration (and reference that project from your Python project).
Take a look at "Project reference for Jython users" (in the end of http://pydev.org/manual_101_project_conf2.html).
I think you could also do what you asked in your question: create a java project, set it as a PyDev project too (right click that project > pydev > set as pydev project) and configure the PyDev project properties setting the PYTHONPATH to the place where you have your Python files and add another entry to the bin folder (i.e.: where the .class files exist). Not sure if it'd be better to keep those as 2 separated projects though.
I think Jython would be ideal here, as the Python code essentially gets translated to Java bytecode and run on the Java virtual machine, making it easy to communicate between the two. Also, pydev itself integrates well with Jython.
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Why not use Jython? The only downside I can immediately think of is if your library uses CPython native extensions.
EDIT: If you can use Jython now but think you may have problems with a later version of the library, I suggest you try to isolate the library from your app (e.g. some sort of adapter interface). Go with the simplest thing that works for the moment, then consider JNI/CPython/etc if and when you ever need to. There's little to be gained by going the (painful) JNI route unless you really have to.
Frankly most ways to somehow run Python directly from within JVM don't work. They are either not-quite-compatible (new release of your third party library can use python 2.6 features and will not work with Jython 2.5) or hacky (it will break with cryptic JVM stacktrace not really leading to solution).
My preferred way to integrate the two would use RPC. XML RPC is not a bad choice here, if you have moderate amounts of data. It is pretty well supported โ Python has it in its standard library. Java libraries are also easy to find. Now depending on your setup either Java or Python part would be a server accepting connection from other language.
A less popular but worth considering alternative way to do RPCs is Google protobuffers, which have 2/3 of support for nice rpc. You just need to provide your transport layer. Not that much work and the convenience of writing is reasonable.
Another option is to write a C wrapper around that pieces of Python functionality that you need to expose to Java and use it via JVM native plugins. You can ease the pain by going with SWIG SWIG.
Essentially in your case it works like that:
- Create a SWIG interface for all method calls from Java to C++.
- Create C/C++ code that will receive your calls and internally call python interpreter with right params.
- Convert response you get from python and send it via swig back to your Java code.
This solution is fairly complex, a bit of an overkill in most cases. Still it is worth doing if you (for some reason) cannot afford RPCs. RPC still would be my preferred choice, though.
On the packages page there's a link (easily overlooked, unfortunately) labeled Compare & Combine Packages. That page basically answers your question:
These packages are provided as a convenience to users; they represent common configurations of Eclipse projects that are often used together. However, since Eclipse is, at its core, an expandable platform, you can easily add other features and plugins to any of these packages. Just choose and install the package that most closely meets your needs, then follow these instructions to add features that you need.
This answer is not meant to point a specific offsite resource, but the principle that comes to play here: using eclipse plugins to add a support for a specific language/feature!
First of all, there is no predefined eclipse build for python.
You can simply install the "Java developer" one and then manually add python support via the eclipse marketplace, for example by installing the pydev plugin.