Multi-project or single-project? and projects layout with large project

Hello. I have a repository which contains several Java library projects and many Java EE projects. I have interdependencies in projects (e.g. many projects are dependent on the library projects). I have these layed out in our repository based on functionality and this works well for us. For example, I have:






I’d like to convert our build system to Gradle. Should I create a root project and sub-projects for each library and EE project or should I create single projects? Also, when I use an IDE to create a root/sub-projects, Gradle seems to want the sub-projects in the directory of the root project (e.g. root/project1) instead of in a subdirectory like we have (e.g. root/a/project1). Is using subdirectories OK? Can anyone point me to some information which would help?