[swig] fix bugs in building Java Wrapper in Windows env

[xuchuanyin]

'CP' is not a valid command in native Windows, which will cause failure in building Java Wrapper.
Use 'COPY' instead and correct the format of file path correspondingly

[jameslamb]

Thanks for your interest in LightGBM and sorry it took so long to get you a review on this!

Thanks for bringing this up. Instead of switching to copy, I think we should make this even more portable by using CMake's file(COPY ...) syntax, as described at https://cmake.org/cmake/help/v3.10/command/file.html.

That way, we could rely on CMake to do this in a way that's portable to different shells.

Could you please try that? And in the other places where this project uses COMMAND cp as well?

LightGBM/CMakeLists.txt

Line 516 in fcf76bc

COMMAND cp "${PROJECT_SOURCE_DIR}/Release/*.dll" com/microsoft/ml/lightgbm/windows/x86_64

LightGBM/CMakeLists.txt

Line 525 in fcf76bc

COMMAND cp "${PROJECT_SOURCE_DIR}/*.dylib" com/microsoft/ml/lightgbm/osx/x86_64

LightGBM/CMakeLists.txt

Lines 526 to 529 in fcf76bc

	COMMAND
	cp
	"${PROJECT_SOURCE_DIR}/lib_lightgbm_swig.jnilib"
	com/microsoft/ml/lightgbm/osx/x86_64/lib_lightgbm_swig.dylib

LightGBM/CMakeLists.txt

Line 537 in fcf76bc

COMMAND cp "${PROJECT_SOURCE_DIR}/*.so" com/microsoft/ml/lightgbm/linux/x86_64

[jameslamb]

Closing this due to lack of response.

I've put up #6259 which I think should address the issue you ran into. Thanks very much for bringing that to our attention! We'd be happy to see you contribute to LightGBM in the future if you have time.