1. import java.util.*;  2.  3. Class FindStuff {  4. public 

题目
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?()
A

Map c = new SortedMap();

B

HashMap c = new HashMap();

C

HashMap c = new Hashtable();

D

SortedMap c = new TreeMap();

如果没有搜索结果或未解决您的问题,请直接 联系老师 获取答案。
相似问题和答案

第1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.

正确答案:C

第2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 A
  • B、 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.

正确答案:E

第3题:

1. public class ReturnIt {  2. return Type methodA(byte x, double y) {  3. return (long)x / y * 2;  4. }  5. }  What is the narrowest valid returnType for methodA in line2?()  

  • A、 int
  • B、 byte
  • C、 long
  • D、 short
  • E、 float
  • F、 double

正确答案:F

第4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())

正确答案:B

第5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.

正确答案:F

第6题:

1. public class a {  2. public void method1() {  3. try {  4. B b=new b();  5. b.method2();  6. // more code here  7. } catch (TestException te) {  8. throw new RuntimeException(te);  9. }  10. }  11. }  1. public class b {  2. public void method2() throws TestException {  3. // more code here  4. }  5. }  1. public class TestException extends Exception {  2. }  Given:  31. public void method() {  32. A a=new a();  33. a.method1();  34. }  Which is true if a TestException is thrown on line 3 of class b?()

  • A、 Line 33 must be called within a try block.
  • B、 The exception thrown by method1 in class a is not required to be caught.
  • C、 The method declared on line 31 must be declared to throw a RuntimeException.
  • D、 On line 5 of class a, the call to method2 of class b does not need to be placed in a try/catch block.

正确答案:B

第7题:

Given a file GrizzlyBear.java:  1. package animals.mammals;  2.  3. public class GrizzlyBear extends Bear {  4. void hunt() {  5. Salmon s = findSalmon();  6. s.consume();  7. }  8. }  and another file, Salmon.java:  1. package animals.fish; 2.  3. public class Salmon extends Fish {  4. void consume() { /* do stuff */ }  5. }  Assume both classes are defined in the correct directories for theft packages, and that the Mammal class correctly defines the findSalmon() method. Which two changes allow this code to compile correctly?()

  • A、 add public to the start of line 4 in Salmon.java
  • B、 add public to the start of line 4 in GrizzlyBear.java
  • C、 add import animals.mammals.*; at line 2 in Salmon.java
  • D、 add import animals.fish.*; at line 2 in GrizzlyBear.java
  • E、 add import animals.fish.Salmon.*; at line 2 in GrizzlyBear.java
  • F、 add import animals.mammals.GrizzlyBear.*;at line 2 in Salmon.java

正确答案:A,D

第8题:

1. public class Target {  2. private int i = 0;  3. public int addOne() {  4. return ++i;  5. }  6. }  And:  1. public class Client {  2. public static void main(String[] args) {  3. System.out.println(new Target().addOne());  4. }  5. }  Which change can you make to Target without affecting Client?() 

  • A、 Line 4 of class Target can be changed to return i++;
  • B、 Line 2 of class Target can be changed to private int i = 1;
  • C、 Line 3 of class Target can be changed to private int addOne() {
  • D、 Line 2 of class Target can be changed to private Integer i = 0;

正确答案:D

第9题:

1. public class Exception Test {  2. class TestException extends Exception {}  3. public void runTest() throws TestException {}  4. public void test() /* Point X */ {  5. runTest();  6. }  7. }  At Point X on line 4, which code is necessary to make the code compile?()  

  • A、 No code is necessary.
  • B、 throws Exception
  • C、 catch ( Exception e )
  • D、 throws RuntimeException
  • E、 catch ( TestException e)

正确答案:B

第10题:

1. public class returnIt (  2. returnType methodA(byte x, double y) (  3. return (short) x/y * 2;  4. )  5. )   What is the valid returnType for methodA in line 2?()  

  • A、 Int
  • B、 Byte
  • C、 Long
  • D、 Short
  • E、 Float
  • F、 Double

正确答案:F

更多相关问题