class A { } class Alpha { private A myA = new A（）； void dolt（ A a ） { a = null； } void tryIt（） { dolt（ myA ）； } } Which two statements are correct？（） A、 There are no instanced of A that will become eligible for garbage collection.B、 Explicitly setting myA to null marks that instance to be eligible for garbage collection.C、 Any call on tryIt（） causes the private instance of A to be marked for garbage collection.D、 Private instances of A become eligible for garbage collection when instances of Alpha become eligible for garbage collection.
class A { } class Alpha { private A myA = new A（）； void dolt（ A a ） { a = null； } void tryIt（） { dolt（ myA ）； } } Which two statements are correct？（）
- A、 There are no instanced of A that will become eligible for garbage collection.
- B、 Explicitly setting myA to null marks that instance to be eligible for garbage collection.
- C、 Any call on tryIt（） causes the private instance of A to be marked for garbage collection.
- D、 Private instances of A become eligible for garbage collection when instances of Alpha become eligible for garbage collection.
相关考题：
1.public class GC{2.private Objec to；3.private void doSomethingElse（Object obj）{o=obj；}4.public void doSomething（）{5.Object o=new Object（）；6.doSomethingElse（o）；7.o=new Object（）；8.doSomethingElse（null）；9.o=null；10.}11.}When the doSomething method is called，after which line does the Object created in line 5 become available for garbage collection？（）A.Line5B.Line6C.Line7D.Line8E.Line9F.Line10
11.class Snoochy{12.Boochybooch；13.public Snoochy（）{booch=newBoochy（this）；}14.}15.16.class Boochy{17.Snoochy snooch；18.public Boochy（Snoochys）{snooch=s；}19.}And the statements：21.public static void main（String[]args）{22.Snoochy snoog=new Snoochy（）；23.snoog=null；24.//more code here25.}Which statement is true about the objects referenced by snoog，snooch，and booch immediately after line 23 executes？（）A.None of these objects are eligible for garbage collection.B.Only the object referenced by booch is eligible for garbage collection.C.Only the object referenced by snoog is eligible for garbage collection.D.Only the object referenced by snooch is eligible for garbage collection.E.The objects referenced by snooch and booch are eligible for garbage collection.
classA{}classAlpha{privateAmyA=newA();voiddolt(Aa){a=null;}voidtryIt(){dolt(myA);}}Whichtwostatementsarecorrect?() A.TherearenoinstancedofAthatwillbecomeeligibleforgarbagecollection.B.ExplicitlysettingmyAtonullmarksthatinstancetobeeligibleforgarbagecollection.C.AnycallontryIt（）causestheprivateinstanceofAtobemarkedforgarbagecollection.D.PrivateinstancesofAbecomeeligibleforgarbagecollectionwheninstancesofAlphabecomeeligibleforgarbagecollection.
class A{void P1(){cout"A111"};void P2(){cout"A222"};};class B:public A{void P1(){cout"B111"};virtual void P2(){cout"B222"};}..........A*cl=NULL;cl=new A;A-P1();A-P2();delete cl;cl=NULL;cl=new B;A-P1();A-P2();delete cl;cl=NULL;..........写出运行结果;
类class one 在声明func 成员函数时发生错误，出错原因是【 】。Class one{private:int a;public:void func(two )};class two{private:int b;friend void one: :func(two );};void one: : func(two r)a=r.b;}
In which two cases does the compiler supply a default constructor for class A？（） A、 class A{}B、 class A { public A（）{} }C、 class A { public A（int x）{} }D、 class Z {} class A extends Z { void A（）{} }
1. class TestA { 2. TestB b； 3. TestA（） { 4. b = new TestB（this）； 5. } 6. } 7. class TestB { 8. TestA a； 9. TestB（TestA a） { 10. this.a = a； 11. } 12. } 13. class TestAll { 14. public static void main （String args[]） { 15. new TestAll（）.makeThings（）； 16. // ...code continues on 17. } 18. void makeThings（） { 19. TestA test = new TestA（）； 20. } 21. } Which two statements are true after line 15， before main completes？（）A、 Line 15 causes a stack overflow.B、 An exception is thrown at runtime.C、 The object referenced by a is eligible for garbage collection.D、 The object referenced by b is eligible for garbage collection.E、 The object referenced by a is not eligible for garbage collection.F、 The object referenced by b is not eligible for garbage collection.
class One { void foo（） {} } class Two extends One { //insert method here } Which three methods， inserted individually at line 14， will correctly complete class Two？（）A、 int foo（） { /* more code here */ }B、 void foo（） { /* more code here */ }C、 public void foo（） { /* more code here */ }D、 private void foo（） { /* more code here */ }E、 protected void foo（） { /* more code here */ }
1. class Test { 2. private Demo d； 3. void start（） { 4. d = new Demo（）； 5. this.takeDemo（d）； 6. } 7. 8. void takeDemo（Demo demo） { 9. demo = null； 10. demo = new Demo（）； 11. } 12. } When is the Demo object， created on line 3， eligible for garbage collection？（） A、 After line 5.B、 After line 9.C、 After the start（） method completes.D、 When the takeDemo（） method completes.E、 When the instance running this code is made eligible for garbage collection.
11.class Snoochy{ 12.Boochybooch； 13.public Snoochy（）{booch=newBoochy（this）；} 14.} 15. 16.class Boochy{ 17.Snoochy snooch； 18.public Boochy（Snoochys）{snooch=s；} 19.} And the statements： 21.public static void main（String[]args）{ 22.Snoochy snoog=new Snoochy（）； 23.snoog=null； 24.//more code here 25.} Which statement is true about the objects referenced by snoog，snooch，and booch immediately after line 23 executes？（）A、None of these objects are eligible for garbage collection.B、Only the object referenced by booch is eligible for garbage collection.C、Only the object referenced by snoog is eligible for garbage collection.D、Only the object referenced by snooch is eligible for garbage collection.E、The objects referenced by snooch and booch are eligible for garbage collection.
Which two allow the class Thing to be instantiated using new Thing（）？A、 public class Thing { }B、 public class Thing { public Thing（） {} }C、 public class Thing { public Thing（void） {} }D、 public class Thing { public Thing（String s） {} }E、 public class Thing { public void Thing（） {} public Thing（String s） {} }
public class Employee{ private String name； public Employee（String name）{ this.name = name； } public void display（）{ System.out.print（name）； } } public class Manager extends Employee{ private String department； public Manager（String name，String department）{ super（name）； this.department = department； } public void display（）{ System.out.println（ super.display（）+”，”+department）； } } 执行语句new Manager（“smith”，”SALES”）后程序的输出是哪项？（） A、 smith，SALESB、 null，SALESC、 smith，nullD、 null，null
interface Animal { void soundOff（）； } class Elephant implements Animal { public void soundOff（） { System.out.println（“Trumpet”）； } } class Lion implements Animal { public void soundOff（） { System.out.println（“Roar”）； } } class Alpha1 { static Animal get（ String choice ） { if （ choice.equalsIgnoreCase（ “meat eater” ）） { return new Lion（）； } else { return new Elephant（）； } } } Which compiles？（） A、 new Animal（）.soundOff（）；B、 Elephant e = new Alpha1（）；C、 Lion 1 = Alpha.get（“meat eater”）；D、 new Alpha1（）.get（“veggie”）.soundOff（）；
public class X { public X aMethod（） { return this；} } public class Y extends X { } Which two methods can be added to the definition of class Y？（）A、 public void aMethod（） {}B、 private void aMethod（） {}C、 public void aMethod（String s） {}D、 private Y aMethod（） { return null； }E、 public X aMethod（） { return new Y（）； }
1.public class GC{ 2.private Objec to； 3.private void doSomethingElse（Object obj）{o=obj；} 4.public void doSomething（）{ 5.Object o=new Object（）； 6.doSomethingElse（o）； 7.o=new Object（）； 8.doSomethingElse（null）； 9.o=null； 10.} 11.} When the doSomething method is called，after which line does the Object created in line 5 become available for garbage collection？（）A、Line5B、Line6C、Line7D、Line8E、Line9F、Line10
Which three will compile and run without exception？（）A、private synchronized Object o；B、void go（）{ synchronized（）{/* code here */}C、public synchronized void go（）{/* code here */}D、private synchronized（this） void go（）{/* code here */}E、void go（）{ synchronized（Object.class）{/* code here */}F、void go（）{ Object o = new Object（）； synchronized（o）{/* code here */}
11. class Snoochy { 12. Boochybooch； 13. public Snoochy（） { booch = new Boochy（this）； } 14. } 15. 16. class Boochy { 17. Snoochy snooch； 18. public Boochy（Snoochy s） { snooch = s； } 19. } And the statements： 21. public static void main（String[] args） { 22. Snoochy snoog = new Snoochy（）； 23. snoog = null； 24. // more code here 25. } Which statement is true about the objects referenced by snoog， snooch， and booch immediately after line 23 executes？（） A、 None of these objects are eligible for garbage collection.B、 Only the object referenced by booch is eligible for garbage collection.C、 Only the object referenced by snoog is eligible for garbage collection.D、 Only the object referenced by snooch is eligible for garbage collection.E、 The objects referenced by snooch and booch are eligible for garbage collection.
public abstract class Shape { private int x； private int y； public abstract void draw（）； public void setAnchor（int x， int y） { this.x = x； this.y = y； } } Which two classes use the Shape class correctly？（）A、 public class Circle implements Shape { private int radius； }B、 public abstract class Circle extends Shape { private int radius； }C、 public class Circle extends Shape { private int radius； public void draw（）； }D、 public abstract class Circle implements Shape { private int radius； public void draw（）； }E、 public class Circle extends Shape { private int radius；public void draw（） {/* code here */} }F、 public abstract class Circle implements Shape { private int radius；public void draw（） { / code here */ } }
Given： 10. class One { 11. void foo（） { } 12. } 13. class Two extends One { 14. //insert method here 15. } Which three methods， inserted individually at line 14， will correctly complete class Two？（）A、 public void foo（） { /* more code here */ }B、 private void foo（） { /* more code here */ }C、 protected void foo（） { /* more code here */ }D、 int foo（） { /* more code here */ } E、 void foo（） { /* more code here */ }
单选题1.public class GC{ 2.private Objec to； 3.private void doSomethingElse（Object obj）{o=obj；} 4.public void doSomething（）{ 5.Object o=new Object（）； 6.doSomethingElse（o）； 7.o=new Object（）； 8.doSomethingElse（null）； 9.o=null； 10.} 11.} When the doSomething method is called，after which line does the Object created in line 5 become available for garbage collection？（）ALine5BLine6CLine7DLine8ELine9FLine10
单选题interface Animal { void soundOff（）； } class Elephant implements Animal { public void soundOff（） { System.out.println（“Trumpet”）； } } class Lion implements Animal { public void soundOff（） { System.out.println（“Roar”）； } } class Alpha1 { static Animal get（ String choice ） { if （ choice.equalsIgnoreCase（ “meat eater” ）） { return new Lion（）； } else { return new Elephant（）； } } } Which compiles？（）A new Animal（）.soundOff（）；B Elephant e = new Alpha1（）；C Lion 1 = Alpha.get（“meat eater”）；D new Alpha1（）.get（“veggie”）.soundOff（）；
单选题11. class Snoochy { 12. Boochybooch； 13. public Snoochy（） { booch = new Boochy（this）； } 14. } 15. 16. class Boochy { 17. Snoochy snooch； 18. public Boochy（Snoochy s） { snooch = s； } 19. } And the statements： 21. public static void main（String[] args） { 22. Snoochy snoog = new Snoochy（）； 23. snoog = null； 24. // more code here 25. } Which statement is true about the objects referenced by snoog， snooch， and booch immediately after line 23 executes？（）A None of these objects are eligible for garbage collection.B Only the object referenced by booch is eligible for garbage collection.C Only the object referenced by snoog is eligible for garbage collection.D Only the object referenced by snooch is eligible for garbage collection.E The objects referenced by snooch and booch are eligible for garbage collection.
单选题1. class Test { 2. private Demo d； 3. void start（） { 4. d = new Demo（）； 5. this.takeDemo（d）； 6. } 7. 8. void takeDemo（Demo demo） { 9. demo = null； 10. demo = new Demo（）； 11. } 12. } When is the Demo object， created on line 3， eligible for garbage collection？（）A After line 5.B After line 9.C After the start（） method completes.D When the takeDemo（） method completes.E When the instance running this code is made eligible for garbage collection.
多选题public class X { public X aMethod（） { return this；} } public class Y extends X { } Which two methods can be added to the definition of class Y？（）Apublic void aMethod（） {}Bprivate void aMethod（） {}Cpublic void aMethod（String s） {}Dprivate Y aMethod（） { return null； }Epublic X aMethod（） { return new Y（）； }
多选题1. class TestA { 2. TestB b； 3. TestA（） { 4. b = new TestB（this）； 5. } 6. } 7. class TestB { 8. TestA a； 9. TestB（TestA a） { 10. this.a = a； 11. } 12. } 13. class TestAll { 14. public static void main （String args[]） { 15. new TestAll（）.makeThings（）； 16. // ...code continues on 17. } 18. void makeThings（） { 19. TestA test = new TestA（）； 20. } 21. } Which two statements are true after line 15， before main completes？（）ALine 15 causes a stack overflow.BAn exception is thrown at runtime.CThe object referenced by a is eligible for garbage collection.DThe object referenced by b is eligible for garbage collection.EThe object referenced by a is not eligible for garbage collection.FThe object referenced by b is not eligible for garbage collection.
多选题class A { } class Alpha { private A myA = new A（）； void dolt（ A a ） { a = null； } void tryIt（） { dolt（ myA ）； } } Which two statements are correct？（）AThere are no instanced of A that will become eligible for garbage collection.BExplicitly setting myA to null marks that instance to be eligible for garbage collection.CAny call on tryIt（） causes the private instance of A to be marked for garbage collection.DPrivate instances of A become eligible for garbage collection when instances of Alpha become eligible for garbage collection.
多选题Which two allow the class Thing to be instantiated using new Thing（）？Apublic class Thing { }Bpublic class Thing { public Thing（） {} }Cpublic class Thing { public Thing（void） {} }Dpublic class Thing { public Thing（String s） {} }Epublic class Thing { public void Thing（） {} public Thing（String s） {} }