We have a couple of applications running on Java 5 and would like now to bring in an application based on Java 6. Can both java versions live together under Windows? Is there any control panel to set the appropiate java version for different applications? ...
This question has been discussed in two blog posts (http://dow.ngra.de/2008/10/27/when-systemcurrenttimemillis-is-too-slow/, http://dow.ngra.de/2008/10/28/what-do-we-really-know-about-non-blocking-concurrency-in-java/), but I haven't heard a definitive answer yet. If we have one thread that does this: public class HeartBeatThread extend...
I have many unused computers at home. What would be the easiest way for me to utilize them to parallelize my C# program with little or no code changes? The task I'm trying to do involves looping through lots of english sentences, the dataset can be easily broken into smaller chunks, processed in different machines concurrently. ...
Microsoft's new F# programming language provides the powerful combination of functional programming (first-class lexical closures and tail calls) with an efficient concurrent garbage collector that makes it easy to leverage multicores. OCaml, Haskell, Erlang and all free Lisp and Scheme implementations that I know of do not have concurr...
Let's say I do something in Java like: RemoteResponse response = null; try { FutureTask task new FutureTask(....); executor.execute(task); response = task.get(1000, TimeUnits.MILLISECONDS); } catch( TimeoutException te ) { .. should I do something special here? ... .. what happens to the return value of the task if ...
Is there any difference between a volatile Object reference and AtomicReference in case I would just use get() and set()-methods from AtomicReference? ...
To recap for those .NET gurus who might not know the Java API: ConcurrentHashMap in Java has atomic methods (i.e. require no external locking) for common Map modification operations such as: putIfAbsent(K key, V value) remove(Object key, Object value) replace(K key, V value) It also allows iteration over the keyset without locking (i...
What is meant by using an explicit memory fence? ...
Dear all, I started with jetlang and the basic samples are pretty clear. What I didn't found is a good sample for using the PoolFiber. Anybody played around with that already? I read also the retlang samples but it seems little bit different there. Thanks for sharing your thoughts! Okami ...
We have a system that is concurrently inserted a large amount of data from multiple stations while also exposing a data querying interface. The schema looks something like this (sorry about the poor formatting): [SyncTable] SyncID StationID MeasuringTime [DataTypeTable] TypeID TypeName [DataTable] SyncID TypeID DataC...
Hi, A client is going to request 1K rows of IDs from the server. I have to make sure we have 1K ID's with clientID = -1, if not, I have to insert 1K new ID's into the table. I then have to link those 1K ID's with the clientID return reserved 1K ID's to the client. Is it as simple as wrapping all of this into a Transaction? ...
I've been looking into improving SQLite performance for my site, especially with regard to transactions. In essence what I'm looking for is a way to defer database writes in a process so that they can all be done at once. However, while I'm accumulating update queries, I would like other processes to be able to both read from and write t...
I'm building a small web app in PHP that stores some information in a plain text file. However, this text file is used/modified by all users of my app at some given point in time and possible at the same time. So the questions is. What would be the best way to make sure that only one user can make changes to the file at any given point ...
The following code is just a simplified example to demonstrate my problem: using System; using System.IO; using System.Diagnostics; using System.Threading; namespace ConsoleApplication5 { class Program { static string LogFile = @"C:\test.log"; static void Main(string[] args) { for (int i = 0...
Let's say I have a List object and an iterator for that list. Now I sort the list with java.util.Collections.sort() What happens to the iterator? Is its behavior still defined and can it still be used? If not, can I prevent destroying the iterators for the list? I know, this problem could be circumvented by changing the program de...
Here's the deal. I have a hash map containing data I call "program codes", it lives in an object, like so: Class Metadata { private HashMap validProgramCodes; public HashMap getValidProgramCodes() { return validProgramCodes; } public void setValidProgramCodes(HashMap h) { validProgramCodes = h; } } I have lots and lots of...
I have created a Registry class in .NET which is a singleton. Apparently this singleton behaves as if it were kept in the Cache (the singleton object is available to each session). Is this a good practice of should I add this Singleton to the Cache? + do I need to wacth out for concurrency problems with the GetInstance() function? names...
In an impersonation scenario related to Sharepoint I need to execute some code in a separate process (the process will run in the context of a certain user). I do not want to launch a separate application, basically I want to do a "run as" on just a method. ...
I am very curious about the possibility of providing immutability for java beans (by beans here I mean classes with an empty constructor providing getters and setters for members). Clearly these classes are not immutable and where they are used to transport values from the data layer this seems like a real problem. One approach to th...
I'm wondering how the concurrency in a web application actually works. Ive read several articles and to my understanding multiple instances of HttpApplication would be working at the same time. Now, I created a simple web app to test concurrency and put the following to global.asax: protected void Application_BeginRequest(object sender,...