Why there's a need of declaring default constructor in java classes?

Answer 1

thanks

Answer 2

constructors are useful since, you cannot initialize values of data in a class since it is a blueprint and not an object itself. initialising using constructors is the only way out of not using many methods and lots of code for the same purpose

Answer 3

You don't, butit can be useful to define a default constructor for cases that you need the methods but not any of the vvariables or whatnot