Comments on: StringBuilder vs. String

By: Javin @ HashMap vs Hashtable in Java

Javin @ HashMap vs Hashtable in Java — Fri, 15 Apr 2011 13:13:33 +0000

Nice article . you may want to check String is immutable in Java as well.

By: Cristian Vrabie

Cristian Vrabie — Fri, 16 Jan 2009 13:15:50 +0000

I did some quick testing: http://cristianvrabie.blogspot.com/2009/01/stringbuilder-vs-string.html
Let’s say I’ve been blown away:

# Runs String StringBuilder
10 0 0
100 2 0
1,000 37 0
10,000 15888 3
10,0000 — 49

*times are in milliseconds

By: Avah

Avah — Fri, 02 Nov 2007 04:05:19 +0000

Joe7Pak: Yes, definitely! The only problem there is the need to pre-allocate 256 characters, but if you know that your target-string is going to be approximately that size, it’s worth it!

By: Joe7Pak

Joe7Pak — Thu, 01 Nov 2007 21:34:01 +0000

Just a thought –

I’m looking in the docs ( for 6.0, don’t know if anything has changed since 5.0 ) and it says that the default ctor for StringBuilder has a buffer of 16 chars. Could it be that if you make the buffer bigger, say, 256 or 512, that you wouldn’t see new StringBuilders being built nearly as much?

By: Avah

Avah — Thu, 30 Mar 2006 18:33:15 +0000

Thank you!

To get the disassembled code, use the javap tool:

javap -c qualified class name

By: Ahmed Hashim

Ahmed Hashim — Thu, 30 Mar 2006 08:20:20 +0000

I was going on to make a Test Script to measure the effect of loading 1 MB file using String concatenation while looping on the file rather than using StringBuffer appending. But I think you did a good job here.:)

BTW how did you make the disassembled code?

Thanks

By: Sandy McArthur

Sandy McArthur — Fri, 17 Feb 2006 05:41:47 +0000

The sort version is if you are joining Strings across many statements, use StringBuilder (or StringBuffer). If you can join Strings in one statement, save your time and use the + operator.