StringBuilder rather than StringBuffer doesn't execute properly in some case

[longgt]

StringBuilder rather than StringBuffer doesn't execute properly in the following case (maybe in for loop)

StringBuffer sb;
for(int i = 0; i < 10; i++) {
  sb = new StringBuffer();
  // Do something
  System.out.println(sb.toString());
}

[Fabrice-TIERCELIN]

Indeed, this case is not handled. The rule is activated only when the object is instantiated once at declaration.