When you select "New Package" off the eclipse menu, the corresponding folder(s) will also be created automatically.
You don't have to define subpackages one level at a time. If I define a new package and enter the package name "com.coderanch.javaranch.saloon.forum", any missing elements in that package tree will also be created automatically.
That's also true in many (though not all) cases where you are prompted by Eclipse to specify/create a directory in general.
An IDE is no substitute for an Intelligent Developer.