Using String Buffer For String Appends in Java

Question

I would like to know if this use of StringBuffer does the same thing as my previous code, because SonarQube asks me not to use += for appending strings.

My previous code :

String sign = "";
if (value < 0) {
    sign.append("-");
}

My new code with StringBuffer :

StringBuffer sign = new StringBuffer();
sign.append("");
if (value < 0) {
    sign.append("-");
}

Is this better this way ?

Thanks for your advices.

Should I use `StringBuilder` instead of `StringBuffer` ? Sonar recommends the second one by the way. — hacks4life, Oct 01 '15 at 09:02
Wait, what? Since when did Sonar recommend the use of StringBuffer instead of StringBuilder? — Tunaki, Oct 01 '15 at 09:03
Rather use `StringBuilder`, this gives you more functionality they just `String` and since `StringBuffer` is designed to be thread safe, it will perform a lot worse than `StringBuilder` (not thread safe) — Nicholas Robinson, Oct 01 '15 at 09:05
Well, one produces a compile time error, the other works. (There is no `append` method in the `String` class). Also it wouldn't work that way, since strings are immutable (e.g. if you use `concat`, a new string is returned). — fabian, Oct 01 '15 at 09:06

score 2 · Accepted Answer · answered Oct 01 '15 at 09:04

Unless you are using that code in a loop, there no bad in your first way (String concatination). For a single attempt you can use that.

As someone commented I assume by writing sign.append("-");, you mean sign +="-"

If you are using in a loop I suggest to use StringBuilder instead of StringBuffer since there is another overhead with StringBuffer is it is synchronized. Unless you need Thread safety, better to change it to StringBuilder.

I'm not sure why SonarQube suggest you to use StringBuffer.

score 1 · Answer 2 · answered Oct 01 '15 at 09:03

1

StringBuffer is better approach that String Concatenation.

Because It will give better memory utilization.

answered Oct 01 '15 at 09:03

Siva Kumar

1,983
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score 0 · Answer 3 · answered Oct 01 '15 at 09:05

0

Yes, it's better way, but StringBuffer is slower than StringBuilder, but synchronized.
If you are using this code is not in a multithreaded application I recommend you use StringBuilder.

answered Oct 01 '15 at 09:05

viartemev

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Using String Buffer For String Appends in Java

3 Answers3