Access modifier for the default constructor is same as the access modifier given to the class.
So if a class has public access, access modifier for default constructor is also public.
In no case a top level class can be protected nor private, so there is no way default constructor be protected nor private.
But we must understand that user defined default constructor can be private, in case you want to implement Singleton
pattern.
[ January 30, 2002: Message edited by: sai k patnala ]