2011年JAVA认证模拟题第二阶段（7）

会计考友

　　Q19.Given the following hierarchical relationship of several classes.
　　1. Object
　　2. |---TypeA
　　3. | |-----TypeAB
' f; A! b! N! b　　4. | |-----TypeAC
" j7 p( M1 X% W4 q# U　　5. |--------TypeY And given the following method definition
　　6. public sayType(Object x ){
　　7. if(x instanceof Object )System.out.print(“Object,”);
& W1 P' b  s4 |% r7 @　　8. if(x instanceof TypeA )System.out.print(“TypeA,”);
　　9. if(x instanceof TypeAB )System.out.print(“TypeAB,”);
　　10. if(x instanceof TypeAC )System.out.print(“TypeAC,”);
　　11. ｝What would the program output be if the following line was executed
9 V2 \0 e% u( `8 j$ Y　　12. sayType( new TypeAB() );
4 o7 q9 ~& h0 O- X9 K7 |; |　　a. Object,
　　b. Object,TypeA,TypeAB,
　　c. TypeAB,
# p9 H& _. k+ U* V& [　　d. Object,TypeAC,
) k. x% ]% T2 _1 C2 [　　Q20.What happens on trying to compile and run the following code?
& a; x- U4 K1 {& h9 A　　1. public class EqualsTest{
% N- p+ ?% g2 b% T, q　　2. public static void main(String args[]){
　　3. Long LA = new Long( 9 ) ;

　　4. Long LB = new Long( 9 ) ;

会计考友

</p>　　5. if( LA == LB ) System.out.println(“Equal”);
　　6. else System.out.println(“Not Equal”);
! Q2 d. X7 y: O7 q　　7. ｝
6 X( X  F% z  k" V* `4 X; H　　8. ｝
: j9 [1 E: n, F5 b　　a. The program compiles but throws a runtime exception in line 5.
5 ?0 V$ E% b7 _　　b. The program compiles and p rints “Not Equal”.
　　c. The program compiles and prints “Equal”.
　　d. The program throws compilation error.
　　Q21.Which one statement in true about the application below?
　　1. class StaticStuff {
　　2. static int x = 10;
7 B( N! J1 y. C; \　　3. static { x += 5; ｝
　　4. public s tatic void main(String args[]) {
　　5. System.out.println(“x = “ + x);
) T% ^8 L3 z9 j4 {& d　　6. ｝
$ \" Q, h: V* [; ?6 X+ G　　7. static { x /= 5; ｝
, [6 x. Y& _  r* c5 I　　8. ｝
　　a. The code compiles, and execution produces the output x = 10.
　　b. The code compiles, and execution produces the output x = 15.
　　c. The code compiles, and execution produces the output x = 3.
! b# I- o5 ~- Q2 \& }　　d. Line 7 will not compile, because you can have only one static initializer.
4 `- t( ?& R0 w: f　　19. b
0 ~  L4 X/ n' T* j$ `　　20. b
　　21. c