JAVA认证历年真题：310-025精选题（8）

会计考友

22. Which are correct class declarations? Assume in each case text constitutes the entire contents of a file called Fred.java on a system
with a case-significant system.
0 ]6 x6 }( S2 [" D1 GA. public class Fred {
" K& h# p! o3 w. a3 c$ q5 U. `public int x = 0;
* ]4 p0 Z/ [5 f2 L/ m9 npublic Fred (int x) {
this.x = x;
}
}
B. public class fred {
public int x = 0;
public fred (int x) {
; _( p2 ?5 i. C# Hthis.x = x;
}
}
C. public class Fred extends MyBaseClass, MyOtherBaseClass {
public int x = 0;
2 h8 `- e* p) G' Tpublic Fred (int xval) {
x = xval;
}
: |, o. f7 w! k, p$ P, _' P8 p}
D. protected class Fred {
private int x = 0;
( |8 F" ]' D2 Yprivate Fred (int xval) {
x = xval;
}
}
E. import java.awt.*;
& W4 {; |1 F  j- U3 e, spublic class Fred extends Object {
" p6 W' ?) L  ]) o+ l6 z* V# jint x;
private Fred (int xval) {
! {7 Z# h) q0 _8 tx = xval;
}
! z9 T3 b& S) x# a: l- a$ \8 {( V}
AE.
5 O6 W9 C1 B) ~0 N& YB is wrong because of case-sensitivity. C is wrong because multiple inheritance is not supported in Java. D is wrong because a class can
. V- G: ]- v, M" K) gonly be public, abstract, final or default (with no access modifier).

会计考友

23. Which are correct class declarations? Assume in each case text constitutes the entire contents of a file called Test.java on a system
with a case-significant system.
A. public class Test {
public int x = 0;
: j& O$ E+ Y( `( B6 upublic Test (int x) {
: z$ z3 j, d: |% k& }# \1 @, Sthis.x = x;
}
+ @1 S- n& ?& V" ]$ ~}
B. public class Test extends MyClass, MyOtherClass {
public int x = 0;
4 z( N: A7 x/ [4 ^, Upublic Test (int xval) {
x = xval;
! |" m9 R: h( u$ {) r}
}
C. import java.awt.*;
. i- h" s/ f+ g) N) bpublic class Test extends Object {
int x;
private Test (int xval) {
; h4 z0 Q/ v2 Q$ l& C$ I; p8 Tx = xval;
}
}
- K9 ^0 x4 G- f6 m8 {D. protected class Test {
2 j) H. W% z+ E3 Z5 Kprivate int x = 0;
private Test (int xval) {
x = xval;
4 `7 O1 j2 A. D2 u& k! m}
}
, H4 N5 O" n8 k/ ?& JAC.
24. A class design requires that a particular member variable must be accesible for direct access by any subclasses of this class,
otherwise not by classes which are not members of the same package. What should be done to achieve this?
A. The variable should be marked public
B. The variable should be marked private
C. The variable should be marked protected
D. The variable should have no special access modifier
" M. K: E5 x4 ^E. The variable should be marked private and an accessor method provided
% k0 Z  O; K# BC.