1. class TestA { 2. TestB b; 3. TestA() { 4. b = new TestB(this); 5. } 6. } 7. class TestB { 8. TestA a; 9. TestB(TestA a) { 10. this.a = a; 11. } 12. } 13. class TestAll { 14. public static void main (String args[]) { 15. new TestAll().makeThings(); 16. // ...code continues on 17. } 18. void makeThings() { 19. TestA test = new TestA(); 20. } 21. } Which two statements are true after line 15, before main completes?()
第1题:
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?()
第2题:
1. public class GoTest { 2. public static void main(String[] args) { 3. Sente a = new Sente(); a.go(); 4. Goban b = new Goban(); b.go(); 5. Stone c = new Stone(); c.go(); 6. } 7. } 8. 9. class Sente implements Go { 10. public void go() { System.out.println(”go in Sente.”); } 11. } 12. 13. class Goban extends Sente { 14. public void go() { System.out.println(”go in Goban”); } 15. } 16. 17. class Stone extends Goban implements Go { } 18. 19. interface Go { public void go(); } What is the result?()
第3题:
classTestA{publicvoidstart(){System.out.println(”TestA”);}}publicclassTestBextendsTestA{publicvoidstart(){System.out.println(”TestB”);}publicstaticvoidmain(String[]args){((TestA)newTestB()).start();}}Whatistheresult?()
A.TestA
B.TestB
C.Compilationfails.
D.Anexceptionisthrownatruntime.
第4题:
class TestA { public void start() { System.out.println(”TestA”); } } public class TestB extends TestA { public void start() { System.out.println(”TestB”); } public static void main(String[] args) { ((TestA)new TestB()).start(); } } What is the result?()
第5题:
1. class A { 2. public byte getNumber () { 3. return 1; 4. } 5. } 6. 7. class B extends A { 8. public short getNumber() { 9. return 2; 10. } 11. 12. public static void main (String args[]) { 13. B b = new B (); 14. System.out.printIn(b.getNumber()) 15. } 16. } What is the result?()
第6题:
1. public class Outer{ 2. public void someOuterMethod() { 3. // Line 3 4. } 5. public class Inner{} 6. public static void main( String[]argv ) { 7. Outer o = new Outer(); 8. // Line 8 9. } 10. } Which instantiates an instance of Inner?()
第7题:
1. public class A { 2. void A() { 3. System.out.println(“Class A”); 4. } 5. public static void main(String[] args) { 6. new A(); 7. } 8. } What is the result?()
第8题:
1. class A { 2. public int getNumber(int a) { 3. return a + 1; 4. } 5. } 6. 7. class B extends A { 8. public int getNumber (int a) { 9. return a + 2 10. } 11. 12. public static void main (String args[]) { 13. A a = new B(); 14. System.out.printIn(a.getNumber(0)); 15. } 16. } What is the result?()
第9题:
1. class Pizza { 2. java.util.ArrayList toppings; 3. public final void addTopping(String topping) { 4. toppings.add(topping); 5. } 6. } 7. public class PepperoniPizza extends Pizza { 8. public void addTopping(String topping) { 9. System.out.println(”Cannot add Toppings”); 10. } 11. public static void main(String[] args) { 12. Pizza pizza = new PepperoniPizza(); 13. pizza.addTopping(”Mushrooms”); 14. } 15. } What is the result?()
第10题:
1. public class Test { 2. public static String output =””; 3. 4. public static void foo(int i) { 5. try { 6. if(i==1) { 7. throw new Exception(); 8. } 9. output += “1”; 10. } 11. catch(Exception e) { 12. output += “2”; 13. return; 14. } 15. finally { 16. output += “3”;17. } 18. output += “4”; 19. } 20. 21. public static void main(String args[]) { 22. foo(0); 23. foo(1); 24. 25. }26. } What is the value of the variable output at line 23?()