Difference between StringBuffer && StringBuilder class?

1.Difference between StringBuffer && StringBuilder class?
StringBuffer class:
all methods are synchronised methods.

StringBuilder class:
All methods are Non-Synchronized methods.


2.Difference between String &&  StringBuilder class?



String class:
all methods are synchronised methods.

StringBuilder class:
All methods are Non-Synchronized methods.

Note: remaining diferences are same as String && StringBuffer class.