Why should the manually managing your stringbuilders be preferable to having the compiler do it for you? The example given is: String result = foo() + arg;

Why should the manually managing your stringbuilders be preferable to having the compiler do it for you? The example given is: String result = foo() + arg; result += boo(); System.out.println(“result = “ + result); creates 3 StringBuilders. I would have thought that it wouldn't be particularly hard to track that the input to subsequent "+" was the output of a previous stringbuilder, allowing easy re-use?