Default constructor: A default constructor is a special method in Java that creates an object of a class with no arguments. It is automatically provided by Java if no other constructors are defined.
Null objects: Null objects are placeholders or dummy objects that have the same interface as real objects but do not perform any meaningful operations. They can be used to avoid NullPointerExceptions by providing default behavior when an actual object is expected but not available.
Object initialization: Object initialization refers to the process of creating and assigning initial values or references to variables within an object. It ensures that all necessary resources are properly allocated before using them in the program.