Java OCA OCP Practice Question 1876

Question

What is the result of compiling and executing the following program? 


package mypkg; //from w  w w .ja va  2s .  c o m

import java.io.*; 
import java.util.*; 

public class Main { 
   private List<String> list = new ArrayList<>(); 
   private static Main getMain(String name) { 
      return null; 
   } 
   public static void printMain() throws Exception { 
      Console c = new Console(); 
      final String name = c.readLine("What is your name?"); 
      final Main stuff = getMain(name); 
      stuff.list.forEach(s -> c.printf(s)); 
   } 
   public static void main(String[] holidays) throws Exception { 
      printMain(); 
   } 
}
  • A. The code does not compile.
  • B. The code compiles and prints a NullPointerException at runtime.
  • C. The code compiles but does not print anything at runtime.
  • D. None of the above


A.

Note

The constructor for Console is private.

Therefore, attempting to call new Console() outside the class results in a compilation error, making Option A the correct answer.

The correct way to obtain a Console instance is to call System.console().

Even if the correct way of obtaining a Console had been used, and the Console was available at runtime, stuff is null in the printMain() method.

Referencing stuff.list results in a NullPointerException, which would make Option B the correct answer.




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