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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();

参考答案

更多 “ 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();” 相关考题
考题 1. public interface A {  2. public void doSomething(String thing);  3. }  1. public class AImpl implements A {  2. public void doSomething(String msg) { }  3. }  1. public class B {  2. public A doit() {  3. // more code here  4. }  5.  6. public String execute() { 7. // more code here  8. }  9. }  1. public class C extends B {  2. public AImpl doit() {  3. // more code here  4. }  5.  6. public Object execute() {  7. // more code here  8. }  9. }  Which statement is true about the classes and interfaces in the exhibit?() A、 Compilation will succeed for all classes and interfaces.B、 Compilation of class C will fail because of an error in line 2.C、 Compilation of class C will fail because of an error in line 6.D、 Compilation of class AImpl will fail because of an error in line 2.

考题 1. public class Test {   2. public static void main (String args) {   3. unsigned byte b = 0;   4. b--;   5.   6. }   7. }   What is the value of b at line 5?()  A、 -1B、 255C、 127D、 Compilation will fail.E、 Compilation will succeed but the program will throw an exception at line 4.

考题 1. public class A {  2. void A() {  3. System.out.println(“Class A”);  4. }  5. public static void main(String[] args) {  6. new A();  7. }  8. }  What is the result?()  A、 Class AB、 Compilation fails.C、 An exception is thrown at line 2.D、 An exception is thrown at line 6.E、 The code executes with no output.

考题 1. class Pizza {  2. java.util.ArrayList toppings;  3. public final void addTopping(String topping) {  4. toppings.add(topping); 5. }  6. }  7. public class PepperoniPizza extends Pizza {  8. public void addTopping(String topping) {  9. System.out.println(”Cannot add Toppings”);  10. }  11. public static void main(String[] args) {  12. Pizza pizza = new PepperoniPizza();  13. pizza.addTopping(”Mushrooms”);  14. }  15. }  What is the result?() A、 Compilation fails.B、 Cannot add ToppingsC、 The code runs with no output.D、 A NullPointerException is thrown in Line 4.

考题 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 1. class A {  2. public String toString ()  {  3. return “4”;  4. }  5. }  6. class B extends A {  7. public String toString ()   {  8. return super.toString()  + “3”;  9. }  10. }  11. public class Test {  12.   public static void main(String[]args)  {  13.      System.out.printIn(new B());  14.      }  15. }    What is the result?()  A、 Compilation succeeds and 4 is printed.B、 Compilation succeeds and 43 is printed.C、 An error on line 9 causes compilation to fail.D、 An error on line 14 causes compilation to fail.E、 Compilation succeeds but an exception is thrown at line 9.

考题 Given a class Repetition: 1.package utils; 2. 3.public class Repetition{ 4.public static String twice(Strings){returns+s;} 5.} and given another class Demo: 1.//insert code here2. 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、importutils.Repetition.*;D、static importutils.Repetition.*;E、import utils.Repetition.twice();F、import static utils.Repetition.twice;G、static import utils.Repetition.twice;

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. private static void process(byte[] b) { }  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、 app.BitUtils.process(bytes);D、 util.BitUtils.process(bytes);E、 import util.BitUtils. *; process(bytes);F、 SomeApp cannot use the process method in BitUtils.

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 1. class A {  3. public String to String() {  4. return “4”;  5. }  6. }  7. class B extends A {  8. public String toString() { 9. return super.toString() + “3”;  10. }  11. }  12. public class Test {  13. public static void main (String[] args) {  14. System.out.printIn(new B()); 15. }  16. }   What is the result( )?   A、 Compilation succeeds and 4 is printed.B、 Compilation …………… is printed.C、 An error on line 9 cause compilation to fail.D、 An error on line 14 cause compilation to fail.E、 Compilation succeeds but an exception is thrown at line 9.

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. interface TestA { String toString(); }  2. public class Test {  3. public static void main(String[] args) {  4. System.out.println(new TestA() {  5. public String toString() { return “test”; }  6. }  7. }  8. }  What is the result?() A、 testB、 nullC、 An exception is thrown at runtime.D、 Compilation fails because of an error in line 1.E、 Compilation fails because of an error in line 4.F、 Compilation fails because of an error in line 5.

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 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1. public class Test {   2. public static void main (String args) {   3. unsigned byte b = 0;   4. b--;   5.   6. }   7. }   What is the value of b at line 5?()A  -1B  255C  127D  Compilation will fail.E  Compilation will succeed but the program will throw an exception at line 4.

考题 单选题Given classes defined in two different files:  1. package util;  2. public class BitUtils {  3. private static void process(byte[] b) { }  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  app.BitUtils.process(bytes);D  util.BitUtils.process(bytes);E  import util.BitUtils. *; process(bytes);F  SomeApp cannot use the process method in BitUtils.

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 单选题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 单选题1. public class A {  2. void A() {  3. System.out.println(“Class A”);  4. }  5. public static void main(String[] args) {  6. new A();  7. }  8. }  What is the result?()A  Class AB  Compilation fails.C  An exception is thrown at line 2.D  An exception is thrown at line 6.E  The code executes with no output.

考题 单选题Given a class Repetition: 1.package utils; 2. 3.public class Repetition{ 4.public static String twice(Strings){returns+s;} 5.} and given another class Demo: 1.//insert code here2. 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 importutils.Repetition.*;D static importutils.Repetition.*;E import utils.Repetition.twice();F import static utils.Repetition.twice;G static import utils.Repetition.twice;