string builder vs string buffer

                                    String vs StringBuilder vs StringBuffer:
String: Immutable version char sequences
StringBuilder: mutable version char sequences,
not synchronized
StringBuffer: mutable version char sequences,
synchronized , thread-safe, slow
String str = new String("a")
StringBuilder s2 = new StringBuilder("B") // MUTABLE
StringBuffer s2 = new StringBuffer("c") // Synchronized 

                                    The main similarity between String and StringBuffer class is that both are
thread safe. 
The main difference is that String is immutable; StringBuffer is mutable.

                                    They both mutable, they are exactly same but
String buffer is thread safe so it runs slower
than String builder.
We are using StringBuffer when we are doing parallel
testing since it is a thread safe.

                                    The StringBuffer and StringBuilder 
class both produces mutable string objects.
 The main difference between 
 them is that StringBuffer is thread safe;
 StringBuilder is not thread safe.

                                    String is immutable and thread safe
String builder mutable and not thread safe