Advantage of Stringbuffer and StringBuilder over String code example

Example 1: stringbuffer vs stringbuilder java

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.

Example 2: stringbuffer vs stringbuilder vs string in java

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.
We are using StringBuffer when we are doing parallel
testing since it is a thread safe.

Example 3: string buffer and string builder

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.