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Which statements describe guaranteed behavior of the garbage collection and finalization mechanisms？（）
- A、Objects are deleted when they can no longer be accessed through any reference.
- B、The finalize（） method will eventually be called on every object.
- C、The finalize（） method will never be called more than once on an object.
- D、An object will not be garbage collected as long as it is possible for an active part of the program to access it through a reference.
- E、The garbage collector will use a mark and sweep algorithm.
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更多 “Which statements describe guaranteed behavior of the garbage collection and finalization mechanisms？（） A、Objects are deleted when they can no longer be accessed through any reference.B、The finalize（） method will eventually be called on every object.C、The finalize（） method will never be called more than once on an object.D、An object will not be garbage collected as long as it is possible for an active part of the program to access it through a reference.E、The garbage collector will use a mark and sweep algorithm.” 相关考题
考题
Which two are true?()
A.A finalizer may NOT be invoked explicitly.B.The finalize method declared in class Object takes no action.C.super.finalize（）is called implicitly by any over riding finalize method.D.The finalize method for a given objec twill be called no more than once by the garbage collector.E.The order in which finalize will be called on two objects is based on the order in which the two objects became finalizable.
考题
Given a class whose instances, when found in a collection of objects, are sorted by using the compareTo()method, which two statements are true?()
A.The class implements java.lang.Comparable.B.The class implements java.util.Comparator.C.The interface used to implement sorting allows this class to define only one sort sequence.D.The interface used to implement sorting allows this class to define many different sort sequences.
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Given:When the doSomething method is called, after which line does the Object created in line 5 become available for garbage collection?()
A.Line 5B.Line 6C.Line 7D.Line 8E.Line 9F.Line 10
考题
Your web application requires the adding and deleting of many session attributes during a complex usecase. A bug report has come in that indicates that an important session attribute is being deleted too soonand a NullPointerException is being thrown several interactions after the fact. You have decided to create asession event listener that will log when attributes are being deleted so you can track down when theattribute is erroneously being deleted. Which listener class will accomplish this debugging goal？（）A、Create an HttpSessionAttributeListener class and implement the attributeDeleted method and log the attribute name using the getName method on the event object.B、Create an HttpSessionAttributeListener class and implement the attributeRemoved method and log the attribute name using the getName method on the event object.C、Create an SessionAttributeListener class and implement the attributeRemoved method and log the attribute name using the getAttributeName method on the event object.D、Create an SessionAttributeListener class and implement the attributeDeleted method and log the attribute name using the getAttributeName method on the event object.
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Which statements concerning the methods notify（） and notifyAll（） are true？ A、Instances of class Thread have a method called notify（）.B、A call to the method notify（） will wake the thread that currently owns the monitor of the object.C、The method notify（） is synchronized.D、The method notifyAll（） is defined in class Thread.E、When there is more than one thread waiting to obtain the monitor of an object， there is no way to be sure which thread will be notified by the notify（） method.
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Which of the following statements about variables and scope are true？（） A、 Local variables defined inside a method are destroyed when the method is exited.B、 Local variables are also called automatic variables.C、 Variables defined outside a method are created when the object is constructed.D、 A method parameter variable continues to exist for as long as the object is needed in which the method is defined.
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Which statement is true for the class java.util.ArrayList？（） A、 The elements in the collection are ordered.B、 The collection is guaranteed to be immutable.C、 The elements in the collection are guaranteed to be unique.D、 The elements in the collection are accessed using a unique key.E、 The elements in the collections are guaranteed to be synchronized.
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Which of the following statements are true？（） A、 The equals（） method determines if reference values refer to the same object.B、 The == operator determines if the contents and type of two separate objects match.C、 The equals（） method returns true only when the contents of two objects match.D、 The class File overrides equals（） to return true if the contents and type of two separate objects match.
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Given a class whose instances， when found in a collection of objects， are sorted by using the compareTo（） method， which two statements are true？（）A、The class implements java.lang.Comparable.B、The class implements java.util.Comparator.C、The interface used to implement sorting allows this class to define only one sort sequence.D、The interface used to implement sorting allows this class to define many different sort sequences.
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Which statements about the garbage collection are true？（） A、 The program developer must create a thread to be responsible for free the memory.B、 The garbage collection will check for and free memory no longer needed.C、 The garbage collection allow the program developer to explicity and immediately free the memory.D、 The garbage collection can free the memory used java object at expect time.
考题
Which two statements are true about using the isUserInRole method to implement security in a Java EEapplication？（）A、It can be invoked only from the doGet or doPost methods.B、It can be used independently of the getRemoteUser method.C、Can return "true" even when its argument is NOT defined as a valid role name in the deployment descriptor.D、Using the isUserInRole method overrides any declarative authentication related to the method in which it is invoked.
考题
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.
考题
class A { } class Alpha { private A myA = new A（）； void dolt（ A a ） { a = null； } void tryIt（） { dolt（ myA ）； } } Which two statements are correct？（） 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.
考题
Which statement is true？（）A、A class’s finalize（） method CANNOT be invoked explicitly.B、super.finalize（） is called implicitly by any overriding finalize（） method.C、The finalize（） method for a given object is called no more than once by the garbage collector.D、The order in which finalize（） is called on two objects is based on the order in which the two objects became finalizable.
考题
Oracle JRockit JVM uses -Xns option to set nursery size when the generational garbage collection mode is used. Which two JVM properties are affected by changing its size ？（）A、 compaction ratio limitB、 garbage collection frequencyC、 garbage collection timesD、 fragmentation heap size
考题
Which three statements are true?（）A、A final method in class X can be abstract if and only if X is abstract.B、A protected method in class X can be overridden by any subclass of X.C、A private static method can be called only within other static methods in class X.D、A non-static public final method in class X can be overridden in any subclass of X.E、A public static method in class X can be called by a subclass of X without explicitly referencing the class X.F、A method with the same signature as a private final method in class X can be implemented in a subclass of X.G、A protected method in class X can be overridden by a subclass of X only if the subclass is in the same package as X.
考题
Which two statements are true about the hashCode method？（）A、The hashCode method for a given class can be used to test for object equality and object inequality for that class.B、The hashCode method is used by the java.util.SortedSet collection class to order the elements within that set.C、The hashCode method for a given class can be used to test for object inequality， but NOT objecte quality， for that class.D、The only important characteristic of the values returned by a hashCode method is that the distribution of values must follow a Gaussian distribution.E、The hashCode method is used by the java.util.HashSet collection class to group the elements within that set into hash buckets for swift retrieval.
考题
多选题Which of the following statements are true？（）AThe equals（） method determines if reference values refer to the same object.BThe == operator determines if the contents and type of two separate objects match.CThe equals（） method returns true only when the contents of two objects match.DThe class File overrides equals（） to return true if the contents and type of two separate objects match.
考题
单选题According to the passage, which of the following statements is TRUE?A
The American ship eventually found a port and dumped its garbage before it returned home.B
Throwaway societies don’t need to transport their refuse and garbage to incinerator because they have a lot of space to put them.C
The wandering ship with garbage reflected the fact that garbage problem became very serious.D
The huge populations of rats swarm through poor neighborhood in many Western European countries because the garbage is thrown into the open dumps.
考题
单选题Which statement is true？（）A
A class’s finalize（） method CANNOT be invoked explicitly.B
super.finalize（） is called implicitly by any overriding finalize（） method.C
The finalize（） method for a given object is called no more than once by the garbage collector.D
The order in which finalize（） is called on two objects is based on the order in which the two objects became finalizable.
考题
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.
考题
多选题Which statements describe guaranteed behavior of the garbage collection and finalization mechanisms？（）AObjects are deleted when they can no longer be accessed through any reference.BThe finalize（） method will eventually be called on every object.CThe finalize（） method will never be called more than once on an object.DAn object will not be garbage collected as long as it is possible for an active part of the program to access it through a reference.EThe garbage collector will use a mark and sweep algorithm.
考题
单选题Given: When the doSomething method is called, after which line does the Object created in line 5 become available for garbage collection?（）A
Line 5B
Line 6C
Line 7D
Line 8E
Line 9F
Line 10
考题
单选题Which statements about the garbage collection are true？（）A
The program developer must create a thread to be responsible for free the memory.B
The garbage collection will check for and free memory no longer needed.C
The garbage collection allow the program developer to explicity and immediately free the memory.D
The garbage collection can free the memory used java object at expect time.
考题
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.
考题
单选题Which statement is true for the class java.util.ArrayList？（）A
The elements in the collection are ordered.B
The collection is guaranteed to be immutable.C
The elements in the collection are guaranteed to be unique.D
The elements in the collection are accessed using a unique key.E
The elements in the collections are guaranteed to be synchronized.
考题
多选题Which two statements are true about using the isUserInRole method to implement security in a Java EEapplication？（）AIt can be invoked only from the doGet or doPost methods.BIt can be used independently of the getRemoteUser method.CCan return true even when its argument is NOT defined as a valid role name in the deployment descriptor.DUsing the isUserInRole method overrides any declarative authentication related to the method in which it is invoked.
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