多项选择题

WhichtwoscenariosareNOTsafetoreplaceaStringBufferobject……

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.

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单项选择题Given： 12.Date date = new Date（）； 13.df.setLocale（Locale.ITALY）； 14.String s = df.format（date）； The variable df is an object of type DateFormat that has been initialized in line 11. What is the result if this code is run on December 14， 2000？（）

A.The value of s is 14-dic-2000.
B.The value of s is Dec 14， 2000.
C.An exception is thrown at runtime.
D.Compilation fails because of an error in line 13.

单项选择题Given： What is the result？（）

A.int Long
B.Short Long
C.Compilation fails.
D.An exception is thrown at runtime.

单项选择题Given： Which statement is true？（）

A.Compilation fails.
B.An exception is thrown at runtime.
C.Synchronizing the run（） method would make the class thread-safe.
D.The data in variable "x" are protected from concurrent access problems.
E.Declaring the doThings（） method as static would make the class thread-safe.

多项选择题Given that Triangle implements Runnable， and： Which two statements， inserted independently at both lines 35 and 41， tend to allow both threads totemporarily pause and allow the other thread to execute？（）

A.Thread.wait（）；
B.Thread.join（）；
C.Thread.yield（）；
D.Thread.sleep（1）；
E.Thread.notify（）；

多项选择题Given： Which three changes should be made to adapt this class to be used safely by multiple threads？（）

A.declare reset（） using the synchronized keyword
B.declare getName（） using the synchronized keyword
C.declare getCount（） using the synchronized keyword
D.declare the constructor using the synchronized keyword
E.declare increment（） using the synchronized keyword