OCJP认证-3期（PX017） 模拟题3.docx

模拟题 3

QUESTION 1

Given:

1. public class Threads4 {

2. public static void main (String[] args) {

3. new Threads4().go();

4. }

5. public void go() {

6. Runnable r = new Runnable() {

13. t.start();

14. }

15. }

What is the result?

A. Compilation fails.

B. An exception is thrown at runtime.

C. The code executes normally and prints "foo".

D. The code executes normally, but nothing is printed.

QUESTION 2

Which two statements are true? (Choose two.)

incorrectly.

F. If a piece of code is capable of deadlocking, you cannot eliminate the possibility of deadlocking

by

inserting invocations of Thread.yield().

QUESTION 3

Given classes defined in two different files:

1. package util;

2. public class BitUtils {

3. public static void process(byte[] b) { /* more code here */ }

4. }

7. }

What is required at line 5 in class SomeApp to use the process method of BitUtils?

A. process(bytes);

B. BitUtils.process(bytes);

C. util.BitUtils.process(bytes);

D. SomeApp cannot use methods in BitUtils.

E. import util.BitUtils.*; process(bytes);

QUESTION 4

A developer is creating a class Book, that needs to access class Paper. The Paper class is deployed

in a

includes /foo/

myLib.jar/Paper.class.

D. The JAR file is located at /foo/myLib.jar and a classpath environment variable is set that

includes /foo/

myLib.jar.

E. The JAR file is located at /foo/myLib.jar and the Book class is compiled using javac -cp

/foo/myLib.jar/

Paper Book.java.

F. The JAR file is located at /foo/myLib.jar and the Book class is compiled using javac -d

/foo/myLib.jar

Book.java

G. The JAR file is located at /foo/myLib.jar and the Book class is compiled using javac -classpath

Given:

11. class Snoochy {

12. Boochy booch;

13. public Snoochy() { booch = new Boochy(this); }

14. }

15.

23. snoog = null;

24. // more code here

25. }

Which statement is true about the objects referenced by snoog, snooch, and booch immediately

after line

23 executes?

A. None of these objects are eligible for garbage collection.

B. Only the object referenced by booch is eligible for garbage collection.

C. Only the object referenced by snoog is eligible for garbage collection.

D. Only the object referenced by snooch is eligible for garbage collection.

Given:

3. public class Batman {

4. int squares = 81;

5. public static void main(String[] args) {

6. new Batman().go();

7. }

8. void go() {

9. incr(++squares);

B. 82

C. 91

D. 92

E. Compilation fails.

F. An exception is thrown at runtime.

QUESTION 7

Given classes defined in two different files:

4. }

1. package app;

2. public class SomeApp {

3. public static void main(String[] args) {

4. byte[] bytes = new byte[256];

5. // insert code here

6. }

7. }

What is required at line 5 in class SomeApp to use the process method of BitUtils?

C. app.BitUtils.process(bytes);

D. util.BitUtils.process(bytes);

E. import util.BitUtils.*; process(bytes);

F. SomeApp cannot use the process method in BitUtils.

QUESTION 8

A UNIX user named Bob wants to replace his chess program with a new one, but he is not sure

where the

old one is installed. Bob is currently able to run a Java chess program starting from his home

A. /test/Chess.class

B. /home/bob/Chess.class

C. /test/games/Chess.class

D. /usr/lib/games/Chess.class

E. /home/bob/games/Chess.class

F. inside jarfile /opt/java/lib/Games.jar (with a correct manifest)

G. inside jarfile /home/bob/downloads/Games.jar (with a correct manifest)

Click the Exhibit button. What is the output of the program shown in the exhibit?