複選題
第38題 Given: 1. class One{ 2. public One foo(){return this;} 3. } 4. class Two extends One{ 5. public One foo(){return this;} 6. } 7. class Three extends Two{ 8. //insert method here 9. } Which two methods, inserted individually, correctly complete the Three class? (Choose two.)
(A) public void foo(){}
(B) public int foo(){return 3;}
(C) public Two foo(){return this;}
(D) public One foo(){return this;}
(E) public Object foo(){return this;}

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.

第37題 Given: 21. abstract class C1{ 22. public C1(){System.out.print(1);} 23. } 24. class C2 extends C1{ 25. public C2(){System.out.print(2);} 26. } 27. class C3 extends C2{ 28. public C3(){System.out.print(3);} 29. } 30. public class Ctest{ 31. public static void main(String[] a){new C3();} 32. } What is the result? (A) 3 (B) 23 (C) 32 (D) 123 (E) 321 F. Compilation fails. G. An exception is thrown at runtime.

第39題 Given: 11. public class ItemTest{ 12. private final int id; 13. public ItemTest(int id){this.id = id;} 14. public void updateId(int newId){id = newId;} 15. 16. public static void main(String[] args){ 17. ItemTest fa = new ItemTest(42); 18. fa.updateId(69); 19. System.out.println(fa.id); 20. } 21. } Which four statments are true? (Choose four.) (A) Compilation fails. (B) An exception is thrown at runtime. (C) The attribute id in the ItemTest object remains unchanged. (D) The attribute id in the ItemTest object is modified to the new value. (E) A new ItemTest object is created with the preferred value in the id attribute.

第40題 SCJP 6.0 認證教戰手冊 黃彬華著 碁峰出版 21 Given: 1. class Foo{ 2. private int x; 3. public Foo(int x){this.x = x;} 4. public void setX(int x){this.x = x;} 5. public int getX(){return x;} 6. } 7. 8. public class Gamma{ 9. static Foo fooBar(Foo foo){ 10. foo = new Foo(100); 11. return foo; 12. } 13. public static void main(String[] args){ 14. Foo foo = new Foo(300); 15. System.out.print(foo.getX() + "-"); 16. 17. Foo fooFoo = fooBar(foo); 18. System.out.print(foo.getX() + "-"); 19. System.out.print(fooFoo.getX() + "-"); 20. 21. foo = fooBar(fooFoo); 22. System.out.print(foo.getX() + "-"); 23. System.out.print(fooFoo.getX()); 24. } 25. } What is the output? (A) 300-100-100-100-100 (B) 300-300-100-100-100 (C) 300-300-300-100-100 (D) 300-300-300-300-100

第41題 Given: 1. public class KungFu{ 2. public static void main(String[] args){ 3. Integer x = 400; 4. Integer y = x; 5. x++; 6. StringBuilder sb1 = new StringBuilder("123"); 7. StringBuilder sb2 = sb1; 8. sb1.append("5"); 9. System.out.println((x == y) + " " + (sb1 == sb2)); 10. } 11. } What is the result? SCJP 6.0 認證教戰手冊 黃彬華著 碁峰出版 22 (A) true true (B) false true (C) true false (D) false false (E) Compilation fails. F. An exception is thrown at runtime.

第42題 1. class A{ 2. public String doit(int x, int y){ 3. return "a"; 4. } 5. 6. public String doit(int... vals){ 7. return "b"; 8. } 9. } Given: 25. A a = new A(); 26. System.out.println(a.doit(4, 5)); What is the result? (A) Line 26 prints "a" to System.out. (B) Line 26 prints "b" to System.out. (C) An exception is thrown at runtime. (D) Compilation of class A will fail due to an error in line 6.

第43題 Given: 1. class Plant{ 2. private String name; 3. public Plant(String name){this.name = name;} 4. public String getName(){return name;} 5. } 6. public class Tree extends Plant{ 7. public void growFruit(){} 8. public void dropLeaves(){} 9. } What statement is true? (A) The code will compile without changes. (B) The code will compile if public Tree(){Plant();} is added to the Tree class. SCJP 6.0 認證教戰手冊 黃彬華著 碁峰出版 23 (C) The code will compile if public Plant(){Tree();} is added to the Plant class. (D) The code will compile if public Plant(){this("fern");} is added to the Plant class. (E) The code will compile if public Plant(){Plant("fern");} is added to the Plant class.

複選題第44題 Given: 1. class Employee{ 2. String name; double baseSalary; 3. public Employee(String name, double baseSalary){ 4. this.name = name; 5. this.baseSalary = baseSalary; 6. } 7. } 8. public class SalesPerson extends Employee{ 9. double commission; 10. public SalesPerson(String name, 11. double baseSalary, double commission){ 12. //insert code here 13. } 14. } Which two code fragments, inserted independently at line 12, will compile? (Choose two.) (A) super(name, baseSalary); (B) this.commission = commission; (C) super(); this.commission = commission; (D) this.commission = commission; super(); (E) super(name, baseSalary); this.commission = commission; F. this.commission = commission; super(name, baseSalary); G. super(name, baseSalary, commission);