List the sequence of call events and return events from time moment 1 to time mo

Question

List the sequence of call events and return events from time moment 1 to time moment 2, e.g.,

• Constructor C(A x) in class C is invoked (call event)

• ?? [multiple steps here]

• The call to constructor C(A x) returns (return event)

• Constructor B(A x) in class B is invoked (call event)

• ?? [multiple steps here] • The call to B(A x) returns (return event)

Basically, you need to fill in the blanks with the rest of the events. Describe precisely which method/constructor in which class is called/returns at each step. Do not omit any events—all calls and returns that happen during this execution should be described in the sequence.

*Note: This is not a coding question and the answer should not be a program/code. Information needed to get the answer is in the code below:

Consider the following Java code: abstract class A private A h; public A(Ax)( this.h-x; if (x != null) x.set(this); } // constructor public A gereturn this.h; public void set (A y) { this. h = y; time moment 1.5 public abstract A p) public static void q(A x) A y yx.get() A z; z-y.p); public void r) Ax; xthis.get() q(x) class B extends A public B(A x)super(x): /constructor: calls A(A x) public A p)return this; class C extends B public C(A xsuper(x); //constructor; calls B(A x) public A get) return this; public A p) f Ax; x this.get ): return x; 1 class Main public static void main(String args) Ax, y: time moment 1 x - new C(null) time moment 2 time moment 3 y new B(x)

Explanation / Answer

Time moment 1: Reference variables x and y of type A are created  

Time moment 1.5:x is initialized to C with its constructor being called with input null and B's constructor getting called with input x.Hence setting the private field to null and x respectively.

Time moment 2:  h is initialized as null in case of x and for y it is initialized to x

Time moment 3: A object x is returned.

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