Java Cookbook : Performance question

[Alvin chew]

hi, wondering the Data Structuring with Generics, foreach, and Enumerations , would it improve significant performance result ? say for "foreach" , will this feature perform better and faster as compare ordinary "for" loop ?

thank you !!

[somkiat puisungnoen]

i think about foreach loop :: it's use to prevent ArrayIndexOutOfBoundException at run time.

[Pradeep bhatt]

I dont see any performance improving because of "enhanced" for loop.

[Jeroen Wenting]

I severely doubt you would. After all the generated bytecode is supposed to be identical to the 1.4 bytecode format.
Any improved performance would therefore be only because the engineers creating the code that effectively creates a traditional for-loop out of the new one create more efficient Java code than you do yourself.
Since there's not much efficiency that can be gained out of for (Iterator i=l.iterator();i.hasNext() {o=i.next(); /* do something with o */ } that's unlikely.
The only real improvement would come from reduced typechecking needed due to the use of generic Lists and Iterators (and even that is limited because those too are expanded).

[Ian Darwin]

wondering the Data Structuring with Generics, foreach, and Enumerations , would it improve significant performance result ? say for "foreach" , will this feature perform better and faster as compare ordinary "for" loop

These features will make developers perform better, by typing less and getting more reliable code.

They won't do very much for runtime performance; if this is an issue you can now buy 2- and 4-CPU AMD Opteron systems.

Ian