Talk:String intern pool
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[edit] question
if you have to do a special operation to get the version in the intern pool why do strings need to be put in the intern pool as soon as they are created (couldn't they just be put in the first time an app looks for them in there?). Plugwash 22:42, 22 January 2006 (UTC)
- String costs a bit of time, but saves memory in the longer run if there are a lot of equal strings. It's a space-time tradeoff. Wouter Lievens 08:21, 22 June 2006 (UTC)
Maybe the historical roots of intern (lisp symbols) should be mentioned? Chkno 20:50, 20 November 2006 (UTC)
The example about finding string duplicates should probably be replaced. It's straightforward to find duplicates in O(n log n) time (just sort the strings, then scan the ordered list; duplicates will be adjacent), and you can get O(n) in practice with a reasonable hash function (hash the strings, use hash table to find potential duplicates). 03:15, 6 December 2006 (UTC)
[edit] Removal of content
I have been bold in updating this page, and removed a bit of content from it which I found inaccurate; notably,
- One disadvantage of the string intern pool is that since every string object must be checked against the pool at creation, there is some performance penalty even if the intern pool is never used by the application. However, due to the possible benefits, this is generally considered acceptable in the languages in which it is implemented.
In neither Java nor the .NET Framework does the string interning occur automatically. It is up to the programmer to explicitly use the intern pool. String literals, however, are always interned anyway, so
String.Intern("Hello World!") // C#
"Hello World!".intern() // Java
don't make much sense. Louis 10:08, 28 January 2007 (UTC) (Edited to make C#'s invocation correct; it's a class method in the .NET Framework. Louis 10:12, 28 January 2007 (UTC))
