Java StringBuilder and String buffer code example

Example 1: 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.

Example 2: 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