Which  statements are true regarding listeners（）

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.

A .  The bus is limited to 32 devices B .  It is a full duplex serial standard C .  It is a half-duplex serial standard D .  It allows up to 320 MB/s of shared channel bandwidth

A . NetFlow records bidirectional IP traffic flow. B . NetFlow export can be implemented over IPv4. C . NetFlow export can be implemented over IPv6. D . NetFlow records multicast IP traffic flow. E . NetFlow records ingress traffic. F . NetFlow records egress traffic.

A . Out-of-profile packets are queued. B . It causes TCP retransmits. C . Marking and remarking are not supported. D . It does not respond to BECN and foresight messages. E . It uses a single- and two-bucket mechanism for metering.

A . A single row subquery can retrieve data from only one table. B . A SQL query statement cannot display data from table B that is referred to in its subquery, unless table B is included in the main query's FROM clause. C . A SQL query statement can display data from table B that is referred to in its subquery, without including table B in its own FROM clause. D . A single row subquery can retrieve data from more than one table. E . A single row subquery cannot be used in a condition where the LIKE operator is used for comparison. F . A multiple-row subquery cannot be used in a condition where the LIKE operator is used for comparison.

A . A subquery that defines a view cannot include the GROUP BY clause  B . A view that is created with the subquery having the DISTINCT keyword can be updated  C . A view that is created with the subquery having the pseudo column ROWNUM keyword cannot be updated  D . A data manipulation language (DML) operation can be performed on a view that is created with the subquery having all the NOT NULL columns of a table

A . RSTP significantly reduces topology reconverging time after a link failure. B . RSTP expends the STP port roles by adding the alternate and backup roles. C . RSTP port states are blocking，discarding，learing，or forwarding. D . RSTP also uses the STP proprsal-agreement sequence. E . RSTP use the same timer-baseed process as STP on point-to-point links. F . RSTP provides a faster transition to the forwarding state on point-to-point links than STP does.

A . Each B channel can transmit up to 64 kbps B . The ISDN B channel carries voice or data C . The ISDN D channel transmits control information. D . The D channel transmission rate varies depending on the service used. E . HDLC or PPP can be used to encapsulate D channel information.

A . WRED can selectively discard lower priority traffic when the interface becomes congested and can provide differentiated performance characteristics for different classes of service. B . Resource Reservation Protocol （RSVP） and WRED cannot be configured on the same interface. C . WRED will throttle back voice traffic only as a last resort. D . If the average queue length is greater than the minimum threshold but less than the maximum threshold， then based on the drop probability， WRED will either queue the packet or perform a random drop. E . WRED statistically drops more packets from low-bandwidth users than high-bandwidth users. Therefore， traffic sources that generate the least traffic are more likely to be slowed down than traffic sources that generate the most traffic. F .  WRED treats non-IP traffic as precedence 4.

A . Has-a relationships should never be encapsulated. B . Has-a relationships should be implemented using inheritance. C . Has-a relationships can be implemented using instance variables. D . Is-a relationships can be implemented using the extends keyword. E . Is-a relationships can be implemented using the implements keyword. F . An array or a collection can be used to implement a one-to-many has-a relationship.

A . Clearing an alert sends the alert to the alert history. B . Response actions cannot be specified with server-generated alerts. C . The nonthreshold alerts appear in the DBA_OUTSTANDING_ALERTS view. D . Server-generated alerts notify the problems that cannot be resolved automatically and requireadministrators to be notified.

A . Asinglerowsubquerycanretrieveonlyonecolumnandonerow. B . Asinglerowsubquerycanretrieveonlyonerowbutmanycolumns. C . Amultiplerowsubquerycanretrievemultiplerowsandmultiplecolumns. D . Amultiplerowsubquerycanbecomparedusingthe"；>；"；operator. E . AsinglerowsubquerycanusetheINoperator. F . Amultiplerowsubquerycanusethe"；="；operator.

A . The checkpoint frequency decreases with the smaller redo log file size. B . It ensures that all committed data is written to the data files during normal shutdown. C . The frequent full checkpoint in a database can cause the overall degradation of the database performance. D . It prompts the Checkpoint （CKPT） process to write data to the data files and redo information to the online redo log files.

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.

A . It is possible for more than two threads to deadlock at once. B . The JVM implementation guarantees that multiple threads cannot enter into a deadlocked state. C . Deadlocked threads release once their sleep（） method’s sleep duration has expired. D . Deadlocking can occur only when the wait（）， notify（）， and notifyAll（） methods are used incorrectly. E . It is possible for a single-threaded application to deadlock if synchronized blocks are used incorrectly. F . If a piece of code is capable of deadlocking， you cannot eliminate the possibility ofdeadlocking by insertinginvocations of Thread.yield（）.

A .  The default constructor initializes method variables. B .  The default constructor has the same access as its class. C .  The default constructor invoked the no-arg constructor of the superclass. D .  If a class lacks a no-arg constructor， the compiler always creates a default constructor.  E .  The compiler creates a default constructor only when there are no other constructors for the class.

A .  In Java programming language only allows single inheritance. B .  In Java programming language allows a class to implement only one interface. C .  In Java programming language a class cannot extend a class and implement a interface together. D .  In Java programming language single inheritance makes code more reliable.

A . The checkpoint frequency decreases with the smaller redo log file size. B . It ensures that all committed data is written to the data files during normal shutdown. C . The frequent full checkpoint in a database can cause the overall degradation of the database performance. D . It prompts the Checkpoint （CKPT） process to write data to the data files and redo information to the onlineredo log file

A . It is possible for more than two threads to deadlock at once. B . The JVM implementation guarantees that multiple threads cannot enter into a deadlocked state. C . Deadlocked threads release once their sleep() method's sleep duration has expired. D . Deadlocking can occur only when the wait(), notify(), and notifyAll() methods are used incorrectly. E . It is possible for a single-threaded application to deadlock if synchronized blocks are used incorrectly. F . If a piece of code is capable of deadlocking, you cannot eliminate the possibility of deadlocking by inserting invocations of Thread.yield().

A . Cisco Express Forwarding （CEF） must be enabled as a prerequisite to running MPLS on a Cisco router. B . Frame-mode MPLS inserts a 32-bit label between the Layer 3 and Layer 4 headers. C . MPLS is designed for use with frame-based Layer 2 encapsulation protocols such as Frame Relay， but is not supported by ATM because of ATM fixed-length cells. D . OSPF， EIGRP， IS-IS， RIP， and BGP can be used in the control plane. E . The control plane is responsible for forwarding packets. F . The two major components of MPLS include the control plane and the data plane.

A .  NAT provides 1 to manyaddress mapping. B .  NAT provides 1 to 1 address mapping. C .  NAT is only useful forTCP/UDP and ICMP traffic. D .  NAT can be used for all IP traffic.

A . It is possible to synchronize static methods. B . When a thread has yielded as a result of yield（）， it releases its locks. C . When a thread is sleeping as a result of sleep（）， it releases its locks. D . The Object.wait（） method can be invoked only from a synchronized context. E . The Thread.sleep（） method can be invoked only from a synchronized context. F . When the thread scheduler receives a notify（） request， and notifies a thread， that thread immediately releases its lock.