Difference between String StringBuffer and StringBuilder

In Java, String, StringBuffer, and StringBuilder are classes used to manipulate strings. Here are the main differences between them:


  1. 1. Immutability:

String is immutable, which means that once a String object is created, it cannot be modified. Any operation that appears to modify a String actually creates a new String object.


StringBuffer and StringBuilder are mutable, which means that they can be modified after creation.


  1. 2. Thread-safety:

String is thread-safe, which means that multiple threads can access and use a String object simultaneously without any issues.


StringBuffer is also thread-safe, as its methods are synchronized to ensure that only one thread can modify the object at a time.


StringBuilder is not thread-safe, which means that it is not safe to use in multi-threaded environments unless proper synchronization is provided.


  1. 3. Performance:

StringBuffer is generally slower than StringBuilder because its methods are synchronized, which can result in slower performance in single-threaded environments.


StringBuilder is faster than StringBuffer because it is not thread-safe and does not incur the overhead of synchronization.


In summary, if you need to manipulate strings in a multi-threaded environment or if you need an immutable string, use String or StringBuffer respectively. If you need to manipulate strings in a single-threaded environment and performance is a concern, use StringBuilder.