Do you know the difference between StringBuilder and string concatenation in Java?

StringBuilder is used for efficient modification of strings within the same object, saving memory during multiple changes. String concatenation with the + operator creates a new string at each step, which can be slower and consume more memory when working with many modifications.

Example of StringBuilder:

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

Example of concatenation with the + operator:

// Using concatenation with the + operator (less efficient for multiple operations)
String result = "";
for (int i = 0; i < 1000; i++) {
    result += "String " + i; // Each operation creates a new string
}

Main differences:

Characteristic	StringBuilder	Concatenation with + operator
Efficiency	High for multiple modifications	Low for multiple modifications
Memory consumption	Economical	Higher
Object creation	Modifies existing object	Creates a new object at each step