Can you name the main classes for working with strings in standard programming language libraries?

In Java, the following main classes are used for working with strings:

• String — an immutable string, the primary class for storing and processing textual data.
• StringBuilder — a mutable string, used for efficient construction and modification of strings without creating new objects.
• StringBuffer — similar to StringBuilder, but thread-safe (synchronized), used in multi-threaded applications.

Example of using StringBuilder:

StringBuilder sb = new StringBuilder();
sb.append("Hello");
sb.append(" ");
sb.append("World");
System.out.println(sb.toString()); // Outputs "Hello World"