Java OCA OCP Practice Question 2983

Question

Given this class definition: 

class Point {
    private int x = 0, y;
    public Point(int x, int y) {
        this.x = x;
        this.y = y;
    }
    // DEFAULT_CTOR
}

Which one of the following definitions of the Point constructor can be replaced without compiler errors in place of the comment DEFAULT_CTOR? 

a) public Point() {
        this(0, 0);
        super();//from w  w  w .  ja v  a 2  s  . c  om
    }

b) public Point() {
        super();
        this(0, 0);
    }

c) private Point() {
        this(0, 0);
    }

d) public Point() {
        this();
    }

e) public Point() {
        this(x, 0);
    }



c)

Note

options a) and b) Both the calls super() and this() cannot be provided in a constructor.

option d) the call this(); will result in a recursive constructor invocation for Point() constructor (and hence the compiler will issue an error).

option e) You cannot refer to an instance field x while explicitly invoking a constructor using this keyword.




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