The use of a StringBuilder or StringBuffer makes String assembly more efficient than plain concatenation
when you perform a large number of appends. Using String concatenation within StringBuilder.append defeats the purpose of
the StringBuilder. If you concatenate only a few strings, use direct String concatenation. Otherwise, replace
String concatenation with calls to append.
This rule applies to String concatenations performed repeatedly, inside loops. In such scenarios, the performance penalty associated with
inefficient StringBuilder.append usage can multiply significantly.
Noncompliant code example
StringBuilder sb = new StringBuilder();
for (String name : names) {
sb.append("Hello : " + name); // Noncompliant
}
Compliant solution
StringBuilder sb = new StringBuilder();
for (String name : names) {
sb.append("Hello : ").append(name);
}
