I have three projects in my eclipse workspace:
EventKitchenCore
EventKitchenDesktop
EventKitchenAndroid
EventKitchenCore
contains
Here is a solution that may help you :
1) Eclipse-Package Explorer - Your Project(Android) - Rightclick on your project.
2) Click on Android (At left side of screen) - Now your screen may look like this -
Now at bottom of screen, in Library section you can add all the library project directly without making any JAR. Just you need to import those library projects in workspace or all your library project should be opened in eclipse.
1) Click on Add button you will get the list of library projects available, choose from them and Build your project.
Good Luck..