多选题 Given:
2. import java.io.*;
3. public class Uboat {
4. public static void main(String[] args) {
5. try {
6. File f1 = new File("sub1");
7. f1.mkdir();
8. File f2 = new File(f1, "sub2");
9. File f3 = new File(f1, "sub3");
10. PrintWriter pw = new PrintWriter(f3);
11. } catch (Exception e) {System.out.println("ouch"); }
12. } }
And, if the code compiles, what is the result if "java Uboat" is invoked TWICE? (Choose all that apply.)

A、 Compilation fails.
B、 The second invocation produces the output "ouch".
C、 The second invocation creates at least one new file as a peer to the new directory.
D、 The first invocation creates a new directory and one new file in that directory.
E、 The first invocation creates a new directory and two new files in that directory.
F、 The first invocation creates a new directory and at least one new file as a peer to it.

【正确答案】 D

【答案解析】