Which method is preferable in terms of performance while adding strings to List/Map?

Question

String or String Builder which one is preferable in the below method ? Kindly explain.

ArrayList<String> list=new ArrayList< String >();
    list.add(new String ("One"));
    list.add(new String ("Two"));
    list.add(new String ("Three"));
    .
    .
    .
    list.add(new String ("N"));

(or)

ArrayList<StringBuilder> list=new ArrayList<StringBuilder>();
    list.add(new StringBuilder("One"));
    list.add(new StringBuilder("Two"));
    list.add(new StringBuilder("Three"));
    .
    .
    .
    list.add(new StringBuilder("N"));

Or `List list = new ArrayList<>(Arrays.asList("One", "Two", "Three", ... "N"));`. — Tom Hawtin - tackline, Oct 09 '18 at 03:33
`in terms of performance..` - so the first approach creates a String Object. The second approach creates a String object and a StringBuilder object. Which do you think is preferable and why? — camickr, Oct 09 '18 at 03:33
There is hardly ever any reason to use the constructor `new String` - `String` is immutable, even the [JavaDocs explicitly mention:](https://docs.oracle.com/javase/10/docs/api/java/lang/String.html#%3Cinit%3E(java.lang.String)) "Unless an explicit copy of original is needed, use of this constructor is unnecessary since Strings are immutable." — Hulk, Oct 09 '18 at 06:10
Neither. You're achieving two different goals as you're constructing lists designated to hold different types of objects. — Janus Varmarken, Oct 09 '18 at 06:33

kvk30 · Answer 1 · 2018-10-09T11:13:19.837

My answer is based on google search not a own answer, I think my small effort help you in better understanding of the topic.

Stringbuilder vs string:

String is immutable whereas StringBuffer and StringBuider are mutable classes.

StringBuffer is thread safe and synchronized whereas StringBuilder is not, thats why StringBuilder is more faster than StringBuffer.

String concat + operator internally uses StringBuffer or StringBuilder class.

Stackoverflow answer

Conclusion/Answer:

Everyone prefer stringbuilder compare to string

score 0 · Answer 2 · answered Oct 09 '18 at 06:30

This is depend on your requirement, if you want to modify object located at certain index then go for string builder. But again if you are working in a multithreaded environment then you have to use string builder carefully as it is a mutable class.

If you are not modifying your list then you must go for String.

Which method is preferable in terms of performance while adding strings to List/Map?

2 Answers2