Which determines if “prefs” is a directory and exists on the file system？（） A、 Boolean exists=Directory.exists （“prefs”）；B、 Boolean exists=（new File（“prefs”））.isDir（）；C、 Boolean exists=（new Directory（“prefs”））.exists（）；D、 Boolean exists=（new File（“prefs”））.isDirectory（）；E、 Boolean exists=true； Try{ Directory d = new Directory（“prefs”）； } catch （FileNotFoundException e） { exists = false； }
Which determines if “prefs” is a directory and exists on the file system？（）
- A、 Boolean exists=Directory.exists （“prefs”）；
- B、 Boolean exists=（new File（“prefs”））.isDir（）；
- C、 Boolean exists=（new Directory（“prefs”））.exists（）；
- D、 Boolean exists=（new File（“prefs”））.isDirectory（）；
- E、 Boolean exists=true； Try{ Directory d = new Directory（“prefs”）； } catch （FileNotFoundException e） { exists = false； }
相关考题：
Object-oriented analysis(OOA)is a semiformal specification technique for the object-oriented paradigm. Object-oriented analysis consists of three steps. The first step is(71). It determines how the various results are computed by the product and presents this information in the form. of a(72)and associated scenarios. The second is(73), which determines the classes and their attributes. Then determine the interrelationships and interaction among the classes. The last step is(74), which determines the actions performed by or to each class or subclass and presents this information in the form. of(75).A．use-case modelingB．class modelingC．dynamic modelingD．behavioral modeling
Which routing algorithm is described below?It is a mechanism in which the sending station determines the route the frame. will follow andincludes the routing information with the flame；bridges read the routing information to determineif they should forward the frame．A．Fixed RoutingB．Spanning TreeC．Source RoutingD．Frame. Forwarding
Object-oriented analysis (OOA) is a semiformal specification technique for the object-oriented paradigm. Object-oriented analysis consists of three steps. The first step is(71) . It determines how the various results are computed by the product and presents this information in the form. of a(72) and associated scenarios. The second is(73) , which determines the classes and their attributes, then determines the interrelationships and interaction among the classes. The last step is(74) , which determines the actions performed by or to each class or subclass and presents this information in the form. of (75) .A．static modelingB．dynamic modelingC．use-case modelingD．behavioral modeling
What is the function of the CSMA／CD algorithm in Ethernet technologies?() A. defines how the media is accessedB. supplies a token to determine which host has access to the mediaC. defines the encoding of electrical signals on the wireD. determines the preamble bits
A receiving host computes the checksum on a frame and determines that the frame is damaged.The frame is then discarded.At which OSI layer did this happen?() A. sessionB. networkC. physicalD. data linkE. transport
Object-oriented analysis（OOA.is a semiformal specification technique for the object-oriented paradigm.Object-oriented analysis consists of three steps.The first step is（ ）.It determines how the various results are computed by the product and presents this information in the form of a（ ）and associated scenarios.The second is（ ），which determines the classes and their attributes.Then determine the interrelationships and interaction among the classes.The last step is（ ）,which determines the actions performed by or to each class or subclass and presents this information in the form of（请作答此空）.A.activity diagramB.component diagramC.sequence diagramD.state diagram
What is the function of the CSMA/CD algorithm in Ethernet technologies?（）A、defines how the media is accessedB、supplies a token to determine which host has access to the mediaC、defines the encoding of electrical signals on the wireD、determines the preamble bits
Part of the job as a network administrator is being able to make a distinction between routed protocols and routing protocols. Which of the following statements is true regarding them?（）A、A routing protocol is assigned to an interface and determines the method of packet delivery.B、A routed protocol is assigned to an interface and determines the method of packet delivery.C、A routing protocol determines the path of a packet through a network.D、A routed protocol determines the path of a packet through a network.E、A routing protocol operates at the transport layer of the OSI model.F、A routed protocol updates the routing table of a router.
Which of the following statements regarding routed and routing protocols are true?（）A、A routed protocol is assigned to an interface and determines the method of packet deliver.B、A routing protocol determines the path of a packet through a network.C、A routed protocol determines the path of a packet through a network.D、A routing protocol operates at the transport layer of the OSI model.E、A routed protocol updates the routing table of a router.
Which of the following BEST describes a hub?（）A、Determines the best route to transmit dataB、Inspects traffic and accepts or declines transmissionC、Broadcasts data to specific network devicesD、Broadcasts data to all network devices
Which of the following determines if the alarm should sound or an entry delay should start？（）A、The sensor itselfB、The way the zones are wiredC、The zone typeD、The digital dialer
By default, which of the following factors determines the spanning-tree path cost?（）A、It is the individual link cost based on latencyB、It is the sum of the costs based on bandwidthC、It is the total hop countD、It is dynamically determined based on load
What protection method is used in 4F MS-SPRing networks？（）A、 Each fiber has half of its capacity reserved for protection.B、 Two fibers carry their full capacities while the other two fibers are reserved for protection.C、 The signal is sent simultaneously in both directions around the ring. The receiver determines which fiber to listen to based on signal quality.D、 The signal is sent simultaneously in both directions around the ring. The transmitter determines which fiber has the working bit set for the receiver to acknowledge.
Which of the following does an astronomical time clock do？（）A、Determines the ambient light at night with a photocell.B、Calculates sunset and sunrise times based on geographical area.C、Determines the start and end of each of the seasons.D、Synchronizes the local time displayed with the official world time.
Which of the following routing protocols runs over UDP and determines path based upon distancevectors?（）A、RIPB、DSIC、BGPD、IS-IS
Which smb.conf configuration keyword determines the hostname resolution order？（）A、 use adsB、 name resolve orderC、 use nsswitch.confD、 use resolv.conf
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.
Which of the following describes how a distributed resumable transaction behaves？（） A、 The resumable setting on the initiating session determines the resumable conditions for the entire distributed transaction.B、 The resumable setting for the initiating instance determines the resumable conditions for the entire distributed transaction.C、 The resumable setting on the initiating session controls only that part of the transaction that occurs within the local instance； remote resumable settings determine the behavior of the distributed parts of the transaction.D、 None of the above.
单选题By default, which of the following factors determines the spanning-tree path cost?（）AIt is the individual link cost based on latencyBIt is the sum of the costs based on bandwidthCIt is the total hop countDIt is dynamically determined based on load
多选题Part of the job as a network administrator is being able to make a distinction between routed protocols and routing protocols. Which of the following statements is true regarding them?（）AA routing protocol is assigned to an interface and determines the method of packet delivery.BA routed protocol is assigned to an interface and determines the method of packet delivery.CA routing protocol determines the path of a packet through a network.DA routed protocol determines the path of a packet through a network.EA routing protocol operates at the transport layer of the OSI model.FA routed protocol updates the routing table of a router.
单选题Which of the following routing protocols runs over UDP and determines path based upon distancevectors?（）ARIPBDSICBGPDIS-IS
单选题A receiving host computes the checksum on a frame and determines that the frame is damaged.Theframe is then discarded.At which OSI layer did this happen?（）AsessionBnetworkCphysicalDdatalinkEtransport
多选题Which of the following statements regarding routed and routing protocols are true?（）AA routed protocol is assigned to an interface and determines the method of packet deliver.BA routing protocol determines the path of a packet through a network.CA routed protocol determines the path of a packet through a network.DA routing protocol operates at the transport layer of the OSI model.EA routed protocol updates the routing table of a router.
单选题Which of the following describes how a distributed resumable transaction behaves？（）A The resumable setting on the initiating session determines the resumable conditions for the entire distributed transaction.B The resumable setting for the initiating instance determines the resumable conditions for the entire distributed transaction.C The resumable setting on the initiating session controls only that part of the transaction that occurs within the local instance； remote resumable settings determine the behavior of the distributed parts of the transaction.D None of the above.
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.
单选题A receiving host computes the checksum on a frame and determines that the frame is damaged.The frame is then discarded.At which OSI layer did this happen?（）AsessionBnetworkCPhysicalDdata linkETransport
单选题What protection method is used in 4F BLSR networks?（）AEach fiber has half of its SONET capacity reserved for protection.BTwo fibers in the span carry working traffic, while the other two fibers in the span are reserved for protection.CThe signal is sent simultaneously in both directions around the ring. The receiver determines which fiber to listen to based on signal quality.DThe signal is sent simultaneously in both directions around the ring. The transmitter determines which fiber has the working bit set for the receiver to acknowledge.