Difference between StringBuffer and StringBuilder

A note on Strings

String is immutable so it cannot be modified once it is instantiated. To modify it, we can create and use StringBuffer or StringBuilder

Difference

StringBuffer is actually thread-safe in a multi-threaded environment by supporting the synchronisation. It means 2 threads cant call the methods of StringBufffer at the same time.Btw, since String also has immutability, it also has stability (thread-safe) in a multi-threaded environment.

Conversely, StringBuilder does not support synchronisation, so it is not suitable for use in a multi-threaded environment, but performance in a single thread is superior to StringBuffer as it does not consider synchronisation.