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10. public class Foo implements java.io.Serializable {  11. private int x;  12. public int getX() { return x; }  12.publicFoo(int x){this.x=x; }  13. private void writeObject( ObjectOutputStream s)  14. throws IOException {  15. // insert code here  16. }  17. }  Which code fragment, inserted at line 15, will allow Foo objects to be correctly serialized and deserialized?() 

  • A、 s.writeInt(x);
  • B、 s.serialize(x);
  • C、 s.writeObject(x);
  • D、 s.defaultWriteObject();

参考答案

更多 “ 10. public class Foo implements java.io.Serializable {  11. private int x;  12. public int getX() { return x; }  12.publicFoo(int x){this.x=x; }  13. private void writeObject( ObjectOutputStream s)  14. throws IOException {  15. // insert code here  16. }  17. }  Which code fragment, inserted at line 15, will allow Foo objects to be correctly serialized and deserialized?() A、 s.writeInt(x);B、 s.serialize(x);C、 s.writeObject(x);D、 s.defaultWriteObject();” 相关考题
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考题 Given:10. interface Data { public void load(); }11. abstract class Info { public abstract void load(); }Which class correctly uses the Data interface and Info class?()() A.B.C.D.E.F.

考题 10. public class ClassA {  11. public void count(int i) {  12. count(++i);  13. }  14. }  And:  20. ClassA a = new ClassA();  21. a.count(3);  Which exception or error should be thrown by the virtual machine?() A、 StackOverflowErrorB、 NullPointerExceptionC、 NumberFormatExceptionD、 IllegalArgumentExceptionE、 ExceptionlnlnitializerError

考题 1. public class Outer{  2. public void someOuterMethod() {  3. // Line 3  4. }  5. public class Inner{}  6. public static void main( String[]argv ) {  7. Outer o = new Outer();  8. // Line 8  9. }  10. }  Which instantiates an instance of Inner?()  A、 new Inner(); // At line 3B、 new Inner(); // At line 8C、 new o.Inner(); // At line 8D、 new Outer.Inner(); // At line 8

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 X {  2. public static void main (String[]args)   {  3. int [] a = new int [1]  4. modify(a);  5. System.out.printIn(a[0]);  6. }  7.    8. public static void modify (int[] a)  {  9.   a[0] ++;  10.    } 11. }       What is the result?()A、 The program runs and prints “0”B、 The program runs and prints “1”C、 The program runs but aborts with an exception.D、 An error “possible undefined variable” at line 4 causes compilation to fail.E、 An error “possible undefined variable” at line 9 causes compilation to fail.

考题 1. public class X {  2. public object m ()  {  3. object o = new float (3.14F);  4. object [] oa = new object [1]; 5. oa[0]= o;  6. o = null;  7. oa[0] = null;  10. return o;  9. }  10. }  When is the float object created in line 3, eligible for garbage collection?()  A、 Just after line 5.B、 Just after line 6.C、 Just after line 7.D、 Just after line 8(that is, as the method returns).

考题 单选题1. public class X {  2. public object m ()  {  3. object o = new float (3.14F);  4. object [] oa = new object [1]; 5. oa[0]= o;  6. o = null;  7. oa[0] = null;  10. return o;  9. }  10. }  When is the float object created in line 3, eligible for garbage collection?()A  Just after line 5.B  Just after line 6.C  Just after line 7.D  Just after line 8(that is, as the method returns).

考题 多选题Given: 10. interface Jumper { public void jump(); } ...   20. class Animal {} ...   30. class Dog extends Animal {   31. Tail tail;   32. }   ...   40. class Beagle extends Dog implements Jumper{   41. public void jump() {}  42. }   ...   50. class Cat implements Jumper{   51. public void jump() {}   52. }. Which three are true?()ACat is-a JumperBCat is-a AnimalCDog is-a JumperDDog is-a AnimalEBeagle has-a JumperFCat has-a AnimalGBeagle has-a Tail

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10. interface Foo { int bar(); }  11. public class Sprite {  12. public int fubar( Foo foo) { return foo.bar(); }  13. public void testFoo() {  14. fubar(  15. // insert code here  16.);  17. }  18. }  Which code, inserted at line 15, allows the class Sprite to compile?()A  Foo { public int bar() { return 1; } }B  new Foo { public int bar() { return 1; } }C  newFoo() { public int bar(){return 1; } }D  new class Foo { public int bar() { return 1; } }

考题 单选题1. public class Outer{  2. public void someOuterMethod() {  3. // Line 3  4. }  5. public class Inner{}  6. public static void main( String[]argv ) {  7. Outer o = new Outer();  8. // Line 8  9. }  10. }  Which instantiates an instance of Inner?()A  new Inner(); // At line 3B  new Inner(); // At line 8C  new o.Inner(); // At line 8D  new Outer.Inner(); // At line 8

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 单选题10. class Line {  11. public class Point { public int x,y; }  12. public Point getPoint() { return new Point(); }  13. }  14. class Triangle {  15. public Triangle() {  16. // insert code here  17. }  18. }  Which code, inserted at line 16, correctly retrieves a local instance of a Point object?()A  Point p = Line.getPoint();B  Line.Point p = Line.getPoint();C  Point p = (new Line()).getPoint();D  Line.Point p = (new Line()).getPoint();

考题 单选题1. interface A { public void aMethod(); }  2. interface B { public void bMethod(); }  3. interface C extends A,B { public void cMethod(); }  4. class D implements B {  5. public void bMethod() { }  6. }  7. class E extends D implements C {  8. public void aMethod() { }  9. public void bMethod() { }  10. public void cMethod() { }  11. }  What is the result?()A  Compilation fails because of an error in line 3.B  Compilation fails because of an error in line 7.C  Compilation fails because of an error in line 9.D  If you define D e = new E(), then e.bMethod() invokes the version of bMethod()defined in Line 5.E  If you define D e = (D)(new E()),then e.bMethod() invokes the version of bMethod() defined in Line 5.F  If you define D e = (D)(new E()), then e.bMethod() invokes the version of bMethod() defined in Line 9.

考题 单选题1. class SuperClass {  2. public a geta() {  3. return new a();  4. }  5. }  6. class SubClass extends SuperClass {  7. public b geta() {  8. return new b();  9. }  10. }  Which is true?()A  Compilation will succeed if a extends b.B  Compilation will succeed if b extends a.C  Compilation will always fail because of an error in line 7.D  Compilation will always fail because of an error in line 8.

考题 单选题1. public class X {  2. public static void main (String[]args)   {  3. int [] a = new int [1]  4. modify(a);  5. System.out.printIn(a[0]);  6. }  7.    8. public static void modify (int[] a)  {  9.   a[0] ++;  10.    } 11. }       What is the result?()A  The program runs and prints “0”B  The program runs and prints “1”C  The program runs but aborts with an exception.D  An error “possible undefined variable” at line 4 causes compilation to fail.E  An error “possible undefined variable” at line 9 causes compilation to fail.

考题 单选题10. public class ClassA {  11. public void count(int i) {  12. count(++i);  13. }  14. }  And:  20. ClassA a = new ClassA();  21. a.count(3);  Which exception or error should be thrown by the virtual machine?()A  StackOverflowErrorB  NullPointerExceptionC  NumberFormatExceptionD  IllegalArgumentExceptionE  ExceptionlnlnitializerError

考题 单选题1. public class test (  2. public static void main(string args[]) {  3. int 1= 0;  4. while (i)  {  5. if (i==4) {  6. break;  7. }  8. ++i;  9. }  10.    11. }  12. )   What is the value of i at line 10?()A  0B  3C  4D  5E  The code will not compile.

考题 多选题10. interface Jumper { public void jump(); }  ......  20. class Animal {}  ......  30. class Dog extends Animal { 31. Tail tail; 32. }  ......  40. class Beagle extends Dog implements Jumper {  41. public void jump() { }  42. }  .......  50. class Cat implements Jumper {  51. public void jump() { }  52. }  Which three are true?()ACat is-a AnimalBCat is-a JumperCDog is-a AnimalDDog is-a JumperECat has-a AnimalFBeagle has-a TailGBeagle has-a Jumper

考题 单选题10. public class ClassA {  11. public void methodA() {  12. ClassB classB = new ClassB();  13. classB.getValue();  14. }  15. }  And:  20. class ClassB {  21. public ClassC classC;  22.  23. public String getValue() {  24. return classC.getValue();  25. }  26. }  And:  30. class ClassC {  31. public String value;  32.  33. public String getValue() {  34. value = “ClassB”;  35. return value;  36. }  37. }  Given:  ClassA a = new ClassA();  a.methodA();  What is the result?()A  Compilation fails.B  ClassC is displayed.C  The code runs with no output.D  An exception is thrown at runtime.

考题 单选题10. class Nav{  11. public enum Direction { NORTH, SOUTH, EAST, WEST }  12. }  13. public class Sprite{  14. // insert code here  15. }  Which code, inserted at line 14, allows the Sprite class to compile?()A  Direction d = NORTH;B  Nav.Direction d = NORTH;C  Direction d = Direction.NORTH;D  Nav.Direction d = Nav.Direction.NORTH;

考题 单选题1.public class Test {  2.public static void main (String args[]) {  3.class Foo {  4.public int i = 3;  5.}  6.Object o = (Object) new Foo();  7.Foo foo = (Foo)o;  8.System.out.printIn(foo. i); 9. }  10.}   What is the result?()A  Compilation will fail.B  Compilation will succeed and the program will print “3”C  Compilation will succeed but the program will throw a ClassCastException at line 6.D  Compilation will succeed but the program will throw a ClassCastException at line 7.

考题 单选题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.