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.
第1题:
3.importjava.util.*;4.classForInTest{5.staticListlist=newArrayList();6.7.publicstaticvoidmain(String[]args){8.list.add("a");list.add("b");list.add("c");9.//insertcodehere10.System.out.print(o);11.}12.}哪一行插入到第9行将导致输出abc”?()
A.for(Objecto:list)
B.for(Iteratoro:list)
C.for(Objecto:list.iterator())
D.for(Iteratoro:list.iterator();o.hasNext();)
第2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3题:
现有:3.importjava.util.*;4.classForInTest{5.staticListlist=newArrayList();6.publicstaticvoidmain(String[]args){7.8.list.add("a");list.add("b");list.add("c");9.//insertcodehere10.System.out.print(o);}}哪一行插入到第9行将导致输出abc”?()
A.for(Objecto:list)
B.for(Iteratoro:list)
C.for(Objecto:list.iterator())
D.for(Iteratoro:list.iterator();o.hasNext();)
第4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5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6题:
现有:
1.importjava.util.*;
2.classForInTest{
3.staticListlist-newArrayList():
4.
5.staticListgetList(){returnlist;}
6.
7.publicstaticvoidmain(Strincj[]args){
8.list.add("a");list.add("b");list.add("c");
9.//insertcodehere
10.System.out.print(o);
11.}
12.}
第9行插入哪一项将输出abc?()
第7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8题:
1.importjava.util.*;2.classForInTest{3.staticListlist=newArrayList();4.5.staticListgetList(){returnlist;}6.7.publicstaticvoidmain(String[]args){8.list.add("a");list.add("b");list.add("c");9.//insertcodehere10.System.out.print(o);11.}12.}第9行插入哪一项将输出abc?()
A.for(charo:list)
B.for(Objecto:getList())
C.for(Objecto:getList();)
D.for(Objecto:o.getList())
第9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10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?()