Java should i use stringbuilder

Skip to content. Change Language. Related Articles. Table of Contents. Save Article. Improve Article. Like Article. Next Reverse a string in Java. Recommended Articles. Article Contributed By :. Creates a string builder whose value is initialized by the specified string, plus an extra 16 empty elements trailing the string. Sets the length of the character sequence. If newLength is less than length , the last characters in the character sequence are truncated.

If newLength is greater than length , null characters are added at the end of the character sequence. Appends the argument to this string builder.

The data is converted to a string before the append operation takes place. The first method deletes the subsequence from start to end-1 inclusive in the StringBuilder 's char sequence. The second method deletes the character located at index. StringBuilder insert int offset, boolean b StringBuilder insert int offset, char c StringBuilder insert int offset, char[] str StringBuilder insert int index, char[] str, int offset, int len StringBuilder insert int offset, double d StringBuilder insert int offset, float f StringBuilder insert int offset, int i StringBuilder insert int offset, long lng StringBuilder insert int offset, Object obj StringBuilder insert int offset, String s.

Inserts the second argument into the string builder. The first integer argument indicates the index before which the data is to be inserted. As you can see in the bytecode, StringBuilder is used. So we don't need to use StringBuilder anymore in Java. However, This is true for the simple cases.

If you need to concatenate inside the loop, it is always suggested to use StringBuilder. For simple string concatenation, you need not use StringBuilder , java compiler will do the trick for you. However, if you need to concatenate inside a loop, you need to manually apply StringBuilder. For better understanding please go to this link.

Edit: The earlier I made this case with only Java 8. Turns out I was wrong. So I stand correct myself. It has nothing to do with java 8. I just did several test cases on real-life code, and I actually don't find any situation where it doesn't use StringBuilders internally.

Quite nice. Ralph: sorry, had a busy week, but I finally got around to dig that up, and as mentioned, I was indeed wrong.

It does create a StringBuilder for each loop turn. I could see situations where it's better that way, but I think they could detect some cases where they could implement an enhanced path detection.

So there's still room for improvement there :. Thanks for having me verify that. I tested with jdk 1. Also I was a bit sceptic about big performance increase as object allocation is so cheap now.

So StringBuilder is still necessary for critical places in similar cases. Show 14 more comments. I dont think StringBuilder has any relation to Builder Pattern. Why are you mixing builder pattern with string builder?

I guess you are trying to explain coding best practices. Why was this answer upvoted even once? The proposed example makes a bad use of the StringBuilder size not preallocated although known, insert makes array copies.

Riaan Cornelius Riaan Cornelius 1, 14 14 silver badges 17 17 bronze badges. Anirudh Ramanathan William Morrison William Morrison Interesting, I wasnt aware of that. Could you provide a reference to which compilers do replace the concatenation and which dont? No, I don't have that information.