Java- Difference between StringBuffer and StringBuilder

StringBuffer	StringBuilder
1)      StringBuffer is synchronized i.e. thread safe. It means two threads can't call the methods of StringBuffer simultaneously.	StringBuilder is non-synchronized i.e. not thread safe. It means two threads can call the methods of StringBuilder simultaneously.
2)      StringBuffer is less efficient than StringBuilder.	StringBuilder is more efficient than StringBuffer.
3)      StringBuffer is slow	StringBuilder is fast