New Enroll for RBI, PFRDA & NABARD Intro Class! April 18 at 9:15 PM

    Question

    What will be the output of the following code snippet

    demonstrating composition in Java? class Engine { void start() {         System.out.println("Engine started.");     }} class Car {     private Engine engine;     Car() {         engine = new Engine(); // Composition     }     void start() {         engine.start();     }} public class Test {     public static void main(String[] args) {         Car car = new Car();         car.start();     }}
    A Engine started. Correct Answer Incorrect Answer
    B Car started. Correct Answer Incorrect Answer
    C No output. Correct Answer Incorrect Answer
    D Compilation error. Correct Answer Incorrect Answer
    E Runtime error. Correct Answer Incorrect Answer

    Solution

    In the provided Java code, the Car class has a composition relationship with the Engine class, meaning that an Engine instance is created within the Car class. When the start method of the Car class is invoked, it calls the start method of the Engine instance, which outputs "Engine started." Therefore, the output of the code is Engine started. Why Other Options Are Wrong: B) Car started: This option is incorrect as there is no start method in the Car class that prints Car started; it delegates to the Engine. C) No output: This option is incorrect because the code clearly produces an output when the start method is called. D) Compilation error: This option is incorrect as the code is syntactically correct and will compile successfully. E) Runtime error: This option is incorrect because there are no conditions in the code that would lead to a runtime error; it executes as intended.

    Practice Next

    Relevant for Exams: