Re: Safety Of Non-Synchronized Collections
On 1/9/13 12:56 PM, Lew wrote:
Roedy Green wrote:
Lew wrote, quoted or indirectly quoted someone who said :
Well, there's the fact that StringBuffer is not thread-safe.
Sun advertised it as such even if it were not perfectly so. When
Never saw it advertised as such myself.
StringBuilder was announced in JDK 1.5 Sun had this to say about
StringBuilder
http://docs.oracle.com/javase/1.5.0/docs/api/java/lang/StringBuilder.html
A mutable sequence of characters. This class provides an API
compatible with StringBuffer, but with no guarantee of
synchronization. This class is designed for use as a drop-in
replacement for StringBuffer in places where the string buffer was
being used by a single thread (as is generally the case). Where
possible, it is recommended that this class be used in preference to
StringBuffer as it will be faster under most implementations.
...
Instances of StringBuilder are not safe for use by multiple threads.
If such synchronization is required then it is recommended that
StringBuffer be used.
Nowhere in the passage you cite does it state that 'StringBuffer' is thread safe.
Directly in StringBuffer JavaDoc, where you'd expect.
From <http://docs.oracle.com/javase/7/docs/api/java/lang/StringBuffer.html>
The first two paragraphs:
A thread-safe, mutable sequence of characters. A string buffer is like a String, but can be modified. At any point in time it contains some particular sequence of characters, but the length and content of the sequence can be changed through certain method calls.
String buffers are safe for use by multiple threads. The methods are synchronized where necessary so that all the operations on any particular instance behave as if they occur in some serial order that is consistent with the order of the method calls made by each of the individual threads involved.
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