What is the StringBuffer class used for in programming?

In Java, the StringBuffer class is used for creating and modifying strings when a mutable sequence of characters is needed. Unlike the String class, whose objects are immutable, StringBuffer allows changing the content without creating new objects.

Main features of StringBuffer:

• Thread-safe (synchronized), making it suitable for multi-threaded environments.
• Allows efficient appending, inserting, deleting, and modifying characters in the string.

Example of usage:

StringBuffer sb = new StringBuffer("Hello");
sb.append(" world");
System.out.println(sb.toString()); // Outputs: Hello world

If thread safety is not required, for better performance, StringBuilder can be used.