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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?() 

  • A、for(char o: list)
  • B、for(Object o: getList())
  • C、for(Object o: getList();)
  • D、for(Object o: o.getList())

参考答案

更多 “ 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?() A、for(char o: list)B、for(Object o: getList())C、for(Object o: getList();)D、for(Object o: o.getList())” 相关考题
考题 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”?() A、 for(Object o : list)B、 for(Iterator o : list)C、 for(Object o : list.iterator())D、 for(Iterator o : list.iterator(); o.hasNext (); )

考题 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?() A、 add this code after line 11: list = (List) list;B、 change lines 12 and 13 to: list.add(”foo”); list.add(”bar”);C、 change the method signature on line 11 to: public void addStrings(List extends String list) {D、 change the method signature on line 11 to: public void addStrings(List super String list) {E、 No changes are necessary. This method compiles without warnings.

考题 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"?() A、  for (Iterator o  :  list.iterator();  o.hasNext  ();  )B、  for (Iterator 0  :  list)C、  for (Object o  :  list.iterator())D、  for (Object o  :  list)

考题 public static void search(List list) {  list.clear();  list.add(”b”);  list.add(”a”);  list.add(”c”);  System.out.println(Collections.binarySearch(list, “a”));  }  What is the result of calling search with a valid List implementation?()A、0B、1C、aD、bE、cF、The result is undefined.

考题 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?()     A、 for(char o: list)B、 for (Object o:  o.getList())C、 for(Object o: getList();)D、 for(Object o: getList())E、 for(Object o: o.getList();)

考题 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?() A、 3,2,1,B、 1,2,3,C、 Compilation fails.D、 The code runs with no output.E、 An exception is thrown at runtime.

考题 1. import java.util.*;  2. public class Example {  3. public static void main(String[] args) {  4. // insert code here  5. set.add(new integer(2));  6. set.add(new integer(l));  7. System.out.println(set);  8. }  9. }  Which code, inserted at line 4, guarantees that this program will output [1,2]? ()A、 Set set = new TreeSet();B、 Set set = new HashSet();C、 Set set = new SortedSet();D、 List set = new SortedList();E、 Set set = new LinkedHashSet();

考题 Given classes defined in two different files:  1. package util;  2. public class BitUtils {  3. public static void process(byte[]) { /* more code here */ }  4. }  1. package app;  2. public class SomeApp {  3. public static void main(String[] args) {  4. byte[] bytes = new byte[256];  5. // insert code here  6. }  7. }  What is required at line 5 in class SomeApp to use the process method of BitUtils?() A、 process(bytes);B、 BitUtils.process(bytes);C、 util.BitUtils.process(bytes);D、 SomeApp cannot use methods in BitUtils.E、 import util.BitUtils.*; process(bytes);

考题 1. public class enclosingone (  2. public class insideone{}  3. )  4. public class inertest(  5. public static void main (string[]args)(  6. enclosingone eo= new enclosingone ();  7. //insert code here  8. )  9. )    Which statement at line 7 constructs an instance of the inner class?()  A、 InsideOnew ei= eo.new InsideOn();B、 Eo.InsideOne ei = eo.new InsideOne();C、 InsideOne ei = EnclosingOne.new InsideOne();D、 EnclosingOne.InsideOne ei = eo.new InsideOne();

考题 Given a class Repetition:  1. package utils;  2.  3. public class Repetition {  4. public static String twice(String s) { return s + s; }  5. }  and given another class Demo:  1. // insert code here 2.  3. public class Demo {  4. public static void main(String[] args) {  5. System.out.println(twice(”pizza”));  6. }  7. }  Which code should be inserted at line 1 of Demo.java to compile and run Demo to print“pizzapizza”?() A、 import utils.*;B、 static import utils.*;C、 import utils.Repetition.*;D、 static import utils.Repetition. *;E、 import utils.Repetition.twice();F、 import static utils.Repetition.twice;G、 static import utils.Repetition.twice;

考题 现有:  1. import java.util.*;      2.  3. Class FindStuff  {  4.public static void main (String[]args)    {      5,    //insert code here      6.    c.put ("X", 123);      7.    }      8.  } 分别插入到第5行,哪三行允许代码编译?()    A、 Map c= new SortedMap();B、 HashMap c= new HashMap();C、 HashMap c= new Hashtalole();D、 SortedMap c= new TreeMap();E、 ArrayList c= new ArrayList();F、  MaD c = new LinkedHashMap();

考题 1. import java.util.*;  2. public class Test {  3. public static void main(String[] args) {  4. List strings = new ArrayList();  5. // insert code here  6. }  7. }  Which four, inserted at line 5, will allow compilation to succeed?()A、 String s = strings.get(0);B、 Iterator i1 = strings.iterator();C、 String[] array1 = strings.toArray();D、 Iterator i2 = strings.iterator();E、 String[] array2 = strings.toArray(new String[1]);F、 Iterator i3 = strings.iterator();

考题 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”?()  A、 for(Object o : list)B、 for(Iterator o : list)C、 for(Object o : list.iterator())D、 for(Iterator o : list.iterator(); o.hasNext (); )

考题 1. import java.util.*;  2.  3. Class FindStuff {  4. public static void  main(String [] args) {  5. // insert code here  6. c.put("x", 123);  7. }  8. } 分别插入到第5行,哪三行允许代码编译?() A、Map c = new SortedMap();B、HashMap c = new HashMap();C、HashMap c = new Hashtable();D、SortedMap c = new TreeMap();

考题 11. public static void append(List list) { list.add(”0042”); }  12. public static void main(String[] args) {  13. List intList = new ArrayList();  14. append(intList);  15. System.out.println(intList.get(0));  16. }  What is the result?() A、 42B、 0042C、 An exception is thrown at runtime.D、 Compilation fails because of an error in line 13.E、 Compilation fails because of an error in line 14.

考题 单选题public static void search(List list) {  list.clear();  list.add(”b”);  list.add(”a”);  list.add(”c”);  System.out.println(Collections.binarySearch(list, “a”));  }  What is the result of calling search with a valid List implementation?()A 0B 1C aD bE cF The result is undefined.

考题 多选题1. import java.util.*;  2. public class Test {  3. public static void main(String[] args) {  4. List strings = new ArrayList();  5. // insert code here  6. }  7. }  Which four, inserted at line 5, will allow compilation to succeed?()AString s = strings.get(0);BIterator i1 = strings.iterator();CString[] array1 = strings.toArray();DIterator i2 = strings.iterator();EString[] array2 = strings.toArray(new String[1]);FIterator i3 = strings.iterator();

考题 单选题11. public static void append(List list) { list.add(”0042”); }  12. public static void main(String[] args) {  13. List intList = new ArrayList();  14. append(intList);  15. System.out.println(intList.get(0));  16. }  What is the result?()A  42B  0042C  An exception is thrown at runtime.D  Compilation fails because of an error in line 13.E  Compilation fails because of an error in line 14.

考题 单选题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?()A  3,2,1,B  1,2,3,C  Compilation fails.D  The code runs with no output.E  An exception is thrown at runtime.

考题 单选题1. import java.util.*;  2. public class Example {  3. public static void main(String[] args) {  4. // insert code here  5. set.add(new integer(2));  6. set.add(new integer(l));  7. System.out.println(set);  8. }  9. }  Which code, inserted at line 4, guarantees that this program will output [1,2]? ()A  Set set = new TreeSet();B  Set set = new HashSet();C  Set set = new SortedSet();D  List set = new SortedList();E  Set set = new LinkedHashSet();

考题 单选题现有:   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”?()A  for(Object o : list)B  for(Iterator o : list)C  for(Object o : list.iterator())D  for(Iterator o : list.iterator(); o.hasNext (); )

考题 单选题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?()A for(char o: list)B for(Object o: getList())C for(Object o: getList();)D for(Object o: o.getList())

考题 单选题1. import java.util.*;  2. class SubGen {  3. public static void main(String [] args) {  4. //insert code here  5. }  6. }  class Alpha { }  class Beta extends Alpha { }  class Gamma extends Beta { }  和四段代码片段:  s1. ArrayList〈? extends Alpha〉 list1 = new ArrayList〈Gamma〉();  s2. ArrayList〈Alpha〉 list2 = new ArrayList〈? extends Alpha〉();  s3. ArrayList〈? extends Alpha〉 list3 = new ArrayList〈? extends Beta〉();  s4. ArrayList〈? extends Beta〉 list4 = new ArrayList〈Gamma〉(); ArrayList〈? extends Alpha〉 list5 = list4;  哪些片段分别插入到第4行,可允许代码编译?()A 只有s1B 只有s3C 只有s1和s3D 只有s1和s4

考题 多选题现有:  1. import java.util.*;      2.  3. Class FindStuff  {  4.public static void main (String[]args)    {      5,    //insert code here      6.    c.put ("X", 123);      7.    }      8.  } 分别插入到第5行,哪三行允许代码编译?()AMap c= new SortedMap();BHashMap c= new HashMap();CHashMap c= new Hashtalole();DSortedMap c= new TreeMap();EArrayList c= new ArrayList();FMaD c = new LinkedHashMap();

考题 多选题1. import java.util.*;  2.  3. Class FindStuff {  4. public static void  main(String [] args) {  5. // insert code here  6. c.put("x", 123);  7. }  8. } 分别插入到第5行,哪三行允许代码编译?()AMap c = new SortedMap();BHashMap c = new HashMap();CHashMap c = new Hashtable();DSortedMap c = new TreeMap();

考题 单选题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?()A  add this code after line 11: list = (List) list;B  change lines 12 and 13 to: list.add(”foo”); list.add(”bar”);C  change the method signature on line 11 to: public void addStrings(List extends String list) {D  change the method signature on line 11 to: public void addStrings(List super String list) {E  No changes are necessary. This method compiles without warnings.

考题 单选题现有:   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”?()A  for(Object o : list)B  for(Iterator o : list)C  for(Object o : list.iterator())D  for(Iterator o : list.iterator(); o.hasNext (); )