【IT書籍】java认证之SCJP考试试题及答案讲解.docVIP

Question 1 Given: 11. public interface Status { 12. /* insert code here */ int MY_VALUE = 10; 13. } Which three are valid on line 12? (Choose three.) A. final B. static C. native D. public E. private F. abstract G. protected A B D Question 2 Given: 10. public class Bar { 11.static void foo(int...x) { 12. // insert code here 13. } 14. } Which two code fragments, inserted independently at line 12, will allow the class to compile? (Choose two.) A. foreach(x) System.out.println(z); B. for(int z : x) System.out.println(z); C. while( x.hasNext()) System.out.println( x.next()); D. for( int i=0; i x.length; i++ ) System.out.println(x[i]); B D Question 3 Given: 11. public class Test { 12. public static void main(String [] args) { 13. int x = 5; 14. boolean b1 = true; 15. boolean b2 = false; 16. 17.if((x==4) !b2) 18. System.out.print(l ); 19. System.out.print(2 ); 20. if ((b2 = true) b1) 21. System.out.print(3 ); 22. } 23. } What is the result? A. 2 B. 3 C. 1 2 D. 2 3 E. 1 2 3 F. Compilation fails. G. Au exceptional is thrown at runtime. D Question 4 Given: 11. String[] elements = { for, tea, too }; 12. String first = (elements.length 0)? elements[0] : null; What is the result? A. Compilation fails. B. An exception is thrown at runtime. C. The variable first is set to null. D. The variable first is set to elements[0]. D Question 5 Given: 10. interface Foo {} 11. class Alpha implements Foo { } 12. class Beta extends Alpha {} 13. class Delta extends Beta { 14. public static void main( String[] args) { 15. Beta x = new Beta(); 16. // insert code here 17. } 18. } Which code, inserted at line 16, will cause a java.lang.ClassCastException? A. Alpha a = x; 隐式向上造型 B. Foo f= (Delta)x; beta不能转换为delta C. Foo f= (Alpha)x; D. Beta b = (Beta)(Alpha)x; B Question 6 Given: 11. class Cup { } 12. class PoisonCup extends Cup { } 21. public void takeCup(Cup c) { 22. if(c instanceof PoisonCup) { 23. System.out.prin