title: What exactly does it mean when they say that StringBuffer class is synchronized? Are all methods of that class declared synchronized?
body: <p>I know that StringBuffer class is synchronized(or thread-safe) while StringBuilder is not. Does this mean that all the methods within StringBuffer such as append are declared with the keyword synchronized ?</p>
  
  <p>I checked the hava API: <a href="http://docs.oracle.com/javase/7/docs/api/java/lang/StringBuffer.html" rel="nofollow">http://docs.oracle.com/javase/7/docs/api/java/lang/StringBuffer.html</a></p>
  
  <p>As per the API, methods such as <code>public StringBuffer append(String str)</code>are not declared with the keyword synchronized. </p>
  
  <p>Can anyone explain?</p>