e.g. Does importing com.MyTest.* also import com.MyTest.UnitTests.*?
No you will have to import the subpackages explicitly. Importing com.MyTest.* will import classes in the package MyTest only. It will not import any class in any of it's subpackage.
Credit: http://www.indiabix.com/technical/java-basics/5
e.g. will the code containing an import such as java.lang.ABCD compile?