Whichtwo scenarios are&#81

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

• AWhen using versions of Java technology earlier than 5.0.
• BWhen sharing a StringBuffer among multiple threads.
• CWhen using the java.io class StringBufferInputStream.
• DWhen you plan to reuse the StringBuffer to build more than one string.
• EEnitiation of separate design processes to the separation of user