第25題 Given: 1. class ClassA{ 2. public int numberOfInstances; 3. protected ClassA(int numberOfInstances){ 4. this.numberOfInstances = numberOfInstances; 5. } 6. } 7. class ExtendedA extends ClassA{ 8. private ExtendedA(int numberOfInstances){ 9. super(numberOfInstances); 10. } 11. public static void main(String[] args){ 12. ExtendedA ext = new ExtendedA(420); 13. System.out.print(ext.numberOfInstances); SCJP 6.0 認證教戰手冊 黃彬華著 碁峰出版 13 14. } 15. } What is the result?
(A) 420 is the output
(B) An exception is thrown at runtime.
(C) All constructors must be declared public.
(D) Constructors CANNOT use the private modifier.
(E) Constructors CANNOT use the protected modifier.

第21題 Given: 1. class Batman{ 2. int squares = 81; 3. public static void main(String[] args){ 4. new Batman().go(); 5. } 6. void go(){ 7. incr(++squares); 8. System.out.println(squares); 9. } 10. void incr(int squares){squares += 10;} 11. } What is the result? SCJP 6.0 認證教戰手冊 黃彬華著 碁峰出版 11 (A) 81 (B) 82 (C) 91 (D) 92 (E) Compilation fails. F. An exception is thrown at runtime.

第22題 Given: 1. class Pass{ 2. public static void main(String[] args){ 3. int x = 5; 4. Pass p = new Pass(); 5. p.doStuff(x); 6. System.out.print(" main x = " + x); 7. } 8. void doStuff(int x){ 9. System.out.println(" doStuff x = " + x++); 10. } 11. } What is the result? (A) Compilation fails. (B) An exception is thrown at runtime. (C) doStuff x = 6 main x = 6 (D) doStuff x = 5 main x = 5 (E) doStuff x = 5 main x = 6 F. doStuff x = 6 main x = 5

複選題第23題 A company has a business application that provides its users with many different reports: receivables reports, payables reports, revenue projects, and so on. The company has just purchased some new, state-of-the-art, wireless printers, and a programmer has been assigned the task of enhancing all of the reports to use not only the company's old printers, but the new wireless printers as well. When the programmer starts looking into the application, the programmer discovers that because of the design of the application, it is necessary to make changes to each report to support the new printers. Which two design concepts most likely explain the situation? (Choose two.) (A) Inheritance SCJP 6.0 認證教戰手冊 黃彬華著 碁峰出版 12 (B) Low cohesion (C) Tight coupling (D) High cohesion (E) Loose coupling F. Object immutablility

第24題 A company that makes Computer Assisted Design(CAD) software has, within its application some utility classes that are used to perform 3D rendering tasks. The company's chief scientist has just improved the performance of one of the utility classes' key rendering algorithms, and has assigned a programmer to replace the old algorithm with the new algorithm. When the programmer begins researching the utility classes, she is happy to discover that the algorithm to be replaced exists in only one class. The programmer reviews that class's API, and replaces the old algorithm with the new algorithm, being careful that her changes adhere strictly to the class's API. Once testing has begun, the programmer discovers that other classes that use the class she changed are no longer working properly. What design flaw is most likely the cause of there new bugs? (A) Inheritance (B) Tight coupling (C) Low cohesion (D) High cohesion (E) Loose coupling F. Object immutablility

複選題第27題 Given: 10. class One{ 11. void foo(){} 12. } SCJP 6.0 認證教戰手冊 黃彬華著 碁峰出版 14 13. class Two extends One{ 14. //insert method here 15. } Which three methods, inserted individually at line 14, will correctly complete class Two? (Choose three.) (A) int foo(){/* more code here */} (B) void foo(){/* more code here */} (C) public void foo(){/* more code here */} (D) private void foo(){/* more code here */} (E) protected void foo(){/* more code here */}

第28題 Given: 1. class X{ 2. X(){System.out.print(1);} 3. X(int x){ 4. this(); 5. System.out.print(2); 6. } 7. } 8. public class Y extends X{ 9. Y(){ 10. super(6); 11. System.out.print(3); 12. } 13. Y(int y){ 14. this(); 15. System.out.println(4); 16. } 17. public static void main(String[] a){new Y(5);} 18. } What is the result? (A) 13 (B) 134 (C) 1234 (D) 2134 (E) 2143 F. 4321

第29題 Given: SCJP 6.0 認證教戰手冊 黃彬華著 碁峰出版 15 1. public class A{ 2. public void doit(){ 3. } 4. public String doit(){ 5. return "a"; 6. } 7. public double doit(int x){ 8. return 1.0; 9. } 10. } What is the result? (A) An exception is thrown at runtime. (B) Compilation fails because of an error in line 7. (C) Compilation fails because of an error in line 4. (D) Compilation succeeds and no runtime errors with class A occur.

第30題 Given: 1. public class SimpleCalc{ 2. public int value; 3. public void calculate(){value += 7;} 4. } And: 1. public class MultiCalc extends SimpleCalc{ 2. public void calculate(){value -= 3;} 3. public void calculate(int multiplier){ 4. calculate(); 5. super.calculate(); 6. value *= multiplier; 7. } 8. public static void main(String[] args){ 9. MultiCalc calculator = new MultiCalc(); 10. calculator.calculate(2); 11. System.out.println("Value is: " + calculator.value); 12. } 13. } What is the result? (A) Value is: 8 (B) Compilation fails. (C) Value is: 12 (D) Value is: -12 (E) The code runs with no output. F. An exception is thrown at runtime.

第31題 Given: 1. public class Base{ 2. public static final String FOO = "foo"; 3. public static void main(String[] args){ 4. Base b = new Base(); 5. Sub s = new Sub(); 6. System.out.print(Base.FOO); 7. System.out.print(Sub.FOO); 8. System.out.print(b.FOO); 9. System.out.print(s.FOO); 10. System.out.print(((Base)s).FOO); 11. } 12. } 13. class Sub extends Base{public static final String FOO = "bar";} What is the result? (A) foofoofoofoofoo (B) foobarfoobarbar (C) foobarfoofoofoo (D) foobarfoobarfoo (E) barbarbarbarbar F. foofoofoobarbar G. foofoofoobarfoo

第35題 Given: 10. public class Hello{ 11. String title; 12. int value; SCJP 6.0 認證教戰手冊 黃彬華著 碁峰出版 18 13. public Hello(){ 14. title += " World"; 15. } 16. public Hello(int value){ 17. this.value = value; 18. title = "Hello"; 19. Hello(); 20. } 21. } and: 30. Hello c = new Hello(5); 31. System.out.print(c.title); What is the result? (A) Hello (B) Hello World (C) Compilation fails. (D) Hello World 5 (E) The code runs with no output. F. An exception is thrown at runtime.