Understanding the folders and files generated by Eclipse

Question

Short version of the question: What are objects.mk, sources.mk, makefile, subdir.mk, *.o and *.d

Answer 1

objects.mk, sources.mk, makefile and subdir.mk are makefiles generated by Eclipse according to your project type (executable, library, shared library). For their contents and how these work refer to the make command documenation of your toolchain. In short these are responsible to call the compiler and linker.

ClassName.o is the object file generated by the compiler, all of them will be linked together to an executable or stored in a library (depending on project type).

ClassName.d is a so called dependency reference file that is generated by the compiler (on demand) and included into the makefiles, that it's possible to track changes in header files, and recompile the concerned source files if neccessary.