Using constructors for creating Objects

Q1. public class Test {}. What is the prototype of the default constructor?
Q2. In which access should a constructor be defined, so that object of the class can be created in any function?
Q3. Default constructor must be defined, if parameterized constructor is defined and the object is to be created without arguments.
Q4. Which of the modifier can't be used for constructor_____?
Q5. The implicit return type of a constructor is_____.