Multiple choice technology web technology

Given: 3. import java.io.*; 4. public class ReadingFor { 5. public static void main(String[] args) { 6. String s; 7. try { 8. FileReader fr = new FileReader("myfile.txt"); 9. BufferedReader br = new BufferedReader(fr); 10. while((s = br.readLine()) != null) 11. System.out.println(s); 12. br.flush(); 13. } catch (IOException e) { System.out.println("io error"); } 16. } 17. } And given that myfile.txt contains the following two lines of data: ab cd What is the result?

  1. ab

  2. abcd

  3. ab cd

  4. a b c D

  5. Compilation fails
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

The variable s is declared but never definitely assigned before use. Although the assignment s = br.readLine() appears in the while condition, Java's definite assignment analysis requires that local variables be assigned before use in a way that can be verified at compile time. The structure of the try-catch block and the while loop creates a scenario where the compiler cannot guarantee s will be assigned, resulting in a compilation error.

AI explanation

BufferedReader doesn't have a flush() method — flush() belongs to the Writer/output side of the I/O API (e.g., BufferedWriter, PrintWriter), not to reader classes. Calling br.flush() on a BufferedReader therefore doesn't compile, regardless of what's in the file or how the try/catch is structured. Since the code never gets past compilation, none of the runtime-output options apply.

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