Exercise 2: Pass by Reference Observation The code given in lecture notes "LectureNotes_part1, page 77 " defines a Java program that explores the concept of passing objects by reference in Java. The PassByRef2 class contains a method 12 which takes an object of the Letter3 class as a parameter, modifles Its flelds, and demonstrates the behavior of object references in Java. The main method creates an instance of the PassByRef 2 class and a Letter 3 object, initializes its fields, and calls the 22 method to observe the changes. Here is the BlueJ diagram that shows relations between two classes: 1. Examine and understand the existing code toat demonstrates the concept of passing objects by reference in Java. 2. Explain the behavior of the program regarding the modification of the Letter object's fields. 3. Print the address of objects in calling function (main method) and in the method f2 where the object fields are modified. By examining the memory locations of the Letter3 object printed, try to understand how pass by reference is implemented. Notice that The address of the object (reference) was copied, not the object! What was the case for "pass by value