Is concatenating with an empty string to do a string conversion really that bad?

Question

Let\'s say I have two char variables, and later on I want to concatenate them into a string. This is how I would do it:

char c1, c2;
// ...

Str         


        

Answer 1

The best way to know is to compile / decompile your code, I used Jad http://en.wikipedia.org/wiki/JAD_(JAva_Decompiler) for that, you will see that your expression was converted into

String s = (new StringBuilder()).append("").append(ci).append(c2).toString();

As you can see javac actually included append("") call, but its cost is negligible, noting is appended to internal StringBuilder buffer, you can check StringBuilder's source