Why is it recommended to use the StringBuilder class for working with strings in Java instead of the usual concatenation operator (+)?

In Java, strings (String) are immutable objects. When using the + operator for string concatenation, a new String object is created each time, which leads to additional memory and time overhead.

The StringBuilder class is designed for efficient string construction by modifying an internal buffer without creating new objects at each step. This is especially important when concatenating a large number of strings, such as in loops.

Example:

StringBuilder sb = new StringBuilder();
for (int i = 0; i < 1000; i++) {
    sb.append(i).append(", ");
}
String result = sb.toString();

This approach is significantly more efficient than using + in a loop.