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单选题
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.


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更多 “单选题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.” 相关考题
考题 1. public class SimpleCalc {  2. public int value;  3. public void calculate() { value += 7; }  4. } And:  1. public class MultiCalc extends SimpleCalc {  2. public void calculate() { value -= 3; }  3. public void calculate(int multiplier) {  4. calculate();  5. super.calculate();  6. value *=multiplier;  7. }  8. public static void main(String[] args) {  9. MultiCalc calculator = new MultiCalc();  10. calculator.calculate(2);  11. System.out.println(”Value is: “+ calculator.value);  12. }  13. }  What is the result?() A、 Value is: 8B、 Compilation fails.C、 Value is: 12D、 Value is: -12E、 The code runs with no output.F、 An exception is thrown at runtime.

考题 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;

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考题 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.

考题 1. public class A {  2. public void doit() {  3. }  4. public String doit() {  5. return “a”;  6. }  7. public double doit(int x) {  8. return 1.0;  9. }  10.}  What is the result?() A、 An exception is thrown at runtime.B、 Compilation fails because of an error in line 7.C、 Compilation fails because of an error in line 4.D、 Compilation succeeds and no runtime errors with class A occur.

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 现有2 个文件:  1. package x;  2. public class X {  3. public static void doX() { System.out.print("doX "); }  4. }  和:  1. class Find {  2. public static void main(String [] args) {  3. //insert code here  4. }  5. }  哪两行分别插入到类Find 的第3 行将编译并产生输出“doX”? ()A、doX();B、X.doX();C、x.X.doX();D、x.X myX = new x.X(); myX.doX();

考题 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 ExceptionC、 catch ( Exception e )D、 throws RuntimeExceptionE、 catch ( TestException e)

考题 1. public class A {  2. public void method1() {  3. B b=new B();  4. b.method2();  5. // more code here  6. }  7. }  1. public class B {  2. public void method2() {  3.C c=new C();  4. c.method3();  5. // more code here  6. }  7. }  1. public class C {  2. public void method3() {  3. // more code here  4. }  5. }  Given:  25. try {  26. A a=new A();  27. a.method1();  28. } catch (Exception e) {  29. System.out.print(”an error occurred”);  30. }  Which two are true if a NullPointerException is thrown on line 3 of class C?()A、 The application will crash.B、 The code on line 29 will be executed.C、 The code on line 5 of class A will execute.D、 The code on line 5 of class B will execute.E、 The exception will be propagated back to line 27.

考题 1. class super {  2. public float getNum() {return 3.0f;}  3. }  4.    5. public class Sub extends Super { 6.   7. }   Which method, placed at line 6, will cause a compiler error?()  A、  Public float getNum()   {return 4.0f; }B、  Public void getNum ()  { }C、  Public void getNum (double d)   { }D、  Public double getNum (float d) {retrun 4.0f; }

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 现有:  1. interface Animal {  2. void eat();  3. }  4.  5. // insert code here  6.  7. public class HouseCat extends Feline {  8. public void eat() { }  9. }   和五个声明:  abstract class Feline implements Animal { }  abstract class Feline implements Animal { void eat(); }  abstract class Feline implements Animal { public void eat(); }  abstract class Feline implements Animal { public void eat() { } }  abstract class Feline implements Animal { abstract public void eat(); }  分别插入到第5行,有几个可以通过编译?() A、0B、1C、2D、3

考题 单选题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 单选题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 ExceptionC  catch ( Exception e )D  throws RuntimeExceptionE  catch ( TestException e)

考题 多选题现有2 个文件:  1. package x;  2. public class X {  3. public static void doX() { System.out.print("doX "); }  4. }  和:  1. class Find {  2. public static void main(String [] args) {  3. //insert code here  4. }  5. }  哪两行分别插入到类Find 的第3 行将编译并产生输出“doX”? ()AdoX();BX.doX();Cx.X.doX();Dx.X myX = new x.X(); myX.doX();

考题 单选题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.

考题 单选题1. public class SimpleCalc {  2. public int value;  3. public void calculate() { value += 7; }  4. } And:  1. public class MultiCalc extends SimpleCalc {  2. public void calculate() { value -= 3; }  3. public void calculate(int multiplier) {  4. calculate();  5. super.calculate();  6. value *=multiplier;  7. }  8. public static void main(String[] args) {  9. MultiCalc calculator = new MultiCalc();  10. calculator.calculate(2);  11. System.out.println(”Value is: “+ calculator.value);  12. }  13. }  What is the result?()A  Value is: 8B  Compilation fails.C  Value is: 12D  Value is: -12E  The code runs with no output.F  An exception is thrown at runtime.

考题 多选题1. public class A {  2. public void method1() {  3. B b=new B();  4. b.method2();  5. // more code here  6. }  7. }  1. public class B {  2. public void method2() {  3.C c=new C();  4. c.method3();  5. // more code here  6. }  7. }  1. public class C {  2. public void method3() {  3. // more code here  4. }  5. }  Given:  25. try {  26. A a=new A();  27. a.method1();  28. } catch (Exception e) {  29. System.out.print(”an error occurred”);  30. }  Which two are true if a NullPointerException is thrown on line 3 of class C?()AThe application will crash.BThe code on line 29 will be executed.CThe code on line 5 of class A will execute.DThe code on line 5 of class B will execute.EThe exception will be propagated back to line 27.

考题 单选题现有:  1. interface Animal {  2. void eat();  3. }  4.  5. // insert code here  6.  7. public class HouseCat extends Feline {  8. public void eat() { }  9. }   和五个声明:  abstract class Feline implements Animal { }  abstract class Feline implements Animal { void eat(); }  abstract class Feline implements Animal { public void eat(); }  abstract class Feline implements Animal { public void eat() { } }  abstract class Feline implements Animal { abstract public void eat(); }  分别插入到第5行,有几个可以通过编译?()A 0B 1C 2D 3

考题 单选题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 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 单选题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;

考题 单选题1. public class A {  2. public void doit() {  3. }  4. public String doit() {  5. return “a”;  6. }  7. public double doit(int x) {  8. return 1.0;  9. }  10.}  What is the result?()A  An exception is thrown at runtime.B  Compilation fails because of an error in line 7.C  Compilation fails because of an error in line 4.D  Compilation succeeds and no runtime errors with class A occur.

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.