Hi,
You know how many types of Strings in java ?
1) String class - Immutable and Thread Safe.
2) StringBuffer Class- Mutable and Thread Safe
3) String Builder Class - Muitable and Not Synchronized.
Each of them has its own feature and use.
Whenever u want to use application where its need constant String u can use String class,
This is deveopment specific from initially.
It is clear,