public static Iterator reverse(List list) { Collections.reverse(list); return list.iterator(); } public static void main(String[] args) { List list = new ArrayList(); list.add(” 1”); list.add(”2”); list.add(”3”); for (Object obj: reverse(list)) System.out.print(obj + “,”); } What is the result?()
第1题:
publicstaticvoidsearch(Listlist){list.clear();list.add(”b”);list.add(”a”);list.add(”c”);System.out.println(Collections.binarySearch(list,a”));}WhatistheresultofcallingsearchwithavalidListimplementation?()
A.0
B.1
C.a
D.b
E.c
F.Theresultisundefined.
第2题:
publicstaticIteratorreverse(Listlist){Collections.reverse(list);returnlist.iterator();}publicstaticvoidmain(String[]args){Listlist=newArrayList();list.add(”1”);list.add(”2”);list.add(”3”);for(Objectobj:reverse(list))System.out.print(obj+,”);}Whatistheresult?()
A.3,2,1,
B.1,2,3,
C.Compilationfails.
D.Thecoderunswithnooutput.
E.Anexceptionisthrownatruntime.
第3题:
11. public void addStrings(List list) { 12. list.add(”foo”); 13. list.add(”bar”); 14. } What must you change in this method to compile without warnings?()
第4题:
现有: 3. import java.util.*; 4. class ForInTest { 5.static List list=new ArrayList(); 6. 7.public static void main (String [] args) { 8.list. add("a"); list. add("b");list. add( "c"); 9. //insert code here 10. System.out.print (o); 11. } 12. } 哪一行插入到第9行将导致输出“abc"?()
第5题:
现有: - list是一个合法的集合引用 - getCollection()返回一个合法集合的引用 哪两个是合法的?()
第6题:
1. import java.util.*; 2. class ForInTest { 3. static List list = new ArrayList(); 4. 5. static List getList() { return list; } 6. 7. public static void main(String [] args) { 8. list.add("a"); list.add("b"); list.add("c"); 9. // insert code here 10. System.out.print(o); 11. } 12. } 第 9 行插入哪一项将输出 abc?()
第7题:
1. import java.util.*; 2. public class Test { 3. public static void main(String[] args) { 4. List
第8题:
11. public static void append(List list) { list.add(”0042”); } 12. public static void main(String[] args) { 13. List
第9题:
42
0042
An exception is thrown at runtime.
Compilation fails because of an error in line 13.
Compilation fails because of an error in line 14.
第10题:
for(Object o : list)
for(Iterator o : list)
for(Object o : list.iterator())
for(Iterator o : list.iterator(); o.hasNext (); )
第11题:
只有s1
只有s3
只有s1和s3
只有s1和s4
第12题:
for(Object o : list)
for(Iterator o : list)
for(Object o : list.iterator())
for(Iterator o : list.iterator(); o.hasNext (); )
第13题:
A.addthiscodeafterline11:list=(List
B.changelines12and13to:list.add
C.changethemethodsignatureonline11to:publicvoidaddStrings(List<extendsString>list){
D.changethemethodsignatureonline11to:publicvoidaddStrings(List<superString>list){
E.Nochangesarenecessary.Thismethodcompileswithoutwarnings.
第14题:
现有: 3.import java.util.*; 4.class ForInTest { 5.static List list = new ArrayList(); 6.public static void main (String [] args){ 7. 8.list.add("a"); list.add("b"); list.add("c"); 9.//insert code here 10.System.out.print(o); } } 哪一行插入到第9行将导致输出“abc”?()
第15题:
10. interface A { void x(); } 11. class B implements A { public void x() { } public voidy() { } } 12. class C extends B { public void x() {} } And: 20. java.util.List list = new java.util.ArrayList(); 21. list.add(new B()); 22. list.add(new C()); 23. for (A a:list) { 24. a.x(); 25. a.y();; 26. } What is the result?()
第16题:
public static void search(List
第17题:
- list 是一个合法的集合引用 - getCollection() 返回一个合法集合的引用 哪两个是合法的()
第18题:
现有: 1. import java.util.*; 2. class ForInTest { 3.static List list - new ArrayList(): 4. 5.static List getList() { return list; } 6. 7.public static void main (Strincj[] args) { 8.list.add("a"); list.add("b"); list.add("c"); 9. //insert code here 10. System.out.print (o); 11. } 12. } 第9行插入哪一项将输出abc?()
第19题:
3. import java.util.*; 4. class ForInTest { 5. static List list = new ArrayList(); 6. 7. public static void main(String [] args) { 8. list.add("a"); list.add("b"); list.add("c"); 9. //insert code here 10. System.out.print(o); 11. } 12. } 哪一行插入到第9行将导致输出“abc”?()
第20题:
for(Object o ; list)
for(Object o : getCollection()
for(Object o : list.iterator()
for(lterator i ; list.iterator() ; i.hasNext () )
for(lterator i=list.iterator(); i.hasNext (); )
第21题:
3,2,1,
1,2,3,
Compilation fails.
The code runs with no output.
An exception is thrown at runtime.
第22题:
for(char o: list)
for(Object o: getList())
for(Object o: getList();)
for(Object o: o.getList())
第23题:
add this code after line 11: list = (List
change lines 12 and 13 to: list.add
change the method signature on line 11 to: public void addStrings(List< extends String> list) {
change the method signature on line 11 to: public void addStrings(List< super String> list) {
No changes are necessary. This method compiles without warnings.