When to use constructor

Yes generally it is preferable to design another class which has all the programming logic and just instantiate this class in the main class i.e. the one with main() method in it.

To call one constructor from another constructor is called constructor chaining in java. This process can be implemented in two ways: Using this() keyword to call the current class constructor within the “same class”. Using super() keyword to call the superclass constructor from the “base class”.

Invoking a constructor from a method No, you cannot call a constructor from a method. The only place from which you can invoke constructors using “this()” or, “super()” is the first line of another constructor . If you try to invoke constructors explicitly elsewhere, a compile time error will be generated.1 Ağu 2019

Yes, as mentioned we can call all the members of a class (methods, variables, and constructors) from instance methods or, constructors.