Which two scenarios are NOT safe to replace a StringBuffer object with a StringBuilder object？（）A、When using versions of Java technology earlier than 5.0.B、When sharing a StringBuffer among multiple threads.C、When using the java.io class StringBufferInput

题目

Which two scenarios are NOT safe to replace a StringBuffer object with a StringBuilder object？（）

A、When using versions of Java technology earlier than 5.0.
B、When sharing a StringBuffer among multiple threads.
C、When using the java.io class StringBufferInputStream.
D、When you plan to reuse the StringBuffer to build more than one string.

更多“Which two scenarios are NOT safe to replace a StringBuffer object with a StringBuilder object？（）A、When using versions of Java technology earlier than 5.0.B、When sharing a StringBuffer among multiple threads.C、When using the java.io class StringBufferInput”相关问题

第1题

public class TestString3 { public static void main（String[] args） { // insert code here System.out.println（s）； } } Which two code fragments， inserted independently at line 3， generate the output 4247？（）A、 String s = “123456789”； s = （s-”123”）.replace（1，3，”24”） - “89”；B、 StringBuffer s = new StringBuffer（”123456789”）； s.delete（0，3）.replace（ 1，3， “24”）.delete（4，6）；C、 StringBuffer s = new StringBuffer（”123456789”）； s.substring（3，6）.delete（ 1 ，3）.insert（1， “24”）；D、 StringBuilder s = new StringBuilder（”123456789”）； s.substring（3，6）.delete（ 1 ，2）.insert（ 1， “24”）；E、 StringBuilder s = new StringBuilder（”123456789”）； s.delete（0，3）.delete（ 1 ，3）.delete（2，5）.insert（ 1， “24”）；

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第2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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第3题

When multiple PPP over Ethernet subscribers connect using the same DSL modem, which two attributes does the ERX use to differentiate between subscribers? （）(Choose two.)A、PPP session IDB、subscriber nameC、source MAC addressD、destination MAC address

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第4题

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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第5题

Which of the following is eliminated when using SATA instead of PATA technology？（）A、Jumper selectionB、Power connectorC、Data port connectorD、Hard drive LEDs

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第6题

Given this method in a class： public String toString（） { StringBuffer buffer = new StringBuffer（）； buffer.append（‟‟）； return buffer.toString（）； } Which is true？（） A、 This code is NOT thread-safe.B、 The programmer can replace StringBuffer with StringBuilder with no other changes.C、 This code will perform well and converting the code to use StringBuilder will not enhance the performance.D、 This code will perform poorly. For better performance， the code should be rewritten： return “”；

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第7题

Which methods from the String and StringBuffer classes modify the object on which they are called？（） A、The charAt（） method of the String class.B、The toUpperCase（） method of the String class.C、The replace（） method of the String class.D、The reverse（） method of the StringBuffer class.E、The length（） method of the StringBuffer class.

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Which two scenarios are NOT safe to replace a StringBuffer object with a StringBuilder object？（）A、When using versions of Java technology earlier than 5.0.B、When sharing a StringBuffer among multiple threads.C、When using the java.io class StringBufferInput

题目

更多“Which two scenarios are NOT safe to replace a StringBuffer object with a StringBuilder object？（）A、When using versions of Java technology earlier than 5.0.B、When sharing a StringBuffer among multiple threads.C、When using the java.io class StringBufferInput”相关问题

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