wood burning stoves 2.0*
The moose likes Struts and the fly likes Is Struts ThreadSafe Big Moose Saloon
  Search | Java FAQ | Recent Topics | Flagged Topics | Hot Topics | Zero Replies
Register / Login
JavaRanch » Java Forums » Frameworks » Struts
Bookmark "Is Struts ThreadSafe" Watch "Is Struts ThreadSafe" New topic
Author

Is Struts ThreadSafe

Rajendra Prakash
Ranch Hand

Joined: Sep 10, 2009
Posts: 293
My interviewer asked , is struts Threadsafe(Is struts Action class thread safe ) . In google am getting different answers.
1. "No Struts is not thread safe " 2. Struts is not only thread-safe but also thread-dependent.
can you give me correct answer with reason.
Rajendra Prakash
Ranch Hand

Joined: Sep 10, 2009
Posts: 293
How to implement Threadsafe and singleton concepts in struts. Is it default or should we implement externally.
Ulf Dittmer
Marshal

Joined: Mar 22, 2005
Posts: 41095
    
  44
Struts is a big framework, and the question of whether or not it's thread-safe can mean different things.

Struts Actions are thread-safe in Struts 2, and NOT thread-safe in Struts 1 unless you make them so (at least that's how I read http://struts.apache.org/2.0.14/docs/comparing-struts-1-and-2.html).

But even Struts 2 is a Java web app, and thus based on objects that are not inherently thread-safe (like HttpSession and ServletContext), so it's perfectly possible to create thread-unsafe web apps using Struts 2. Your code needs to take appropriate measures to guard against any concurrency issues when those are involved.

I generally recommend getting a good book on Java concurrency (the ones by Oaks/Wong and Doug Lea in particular); they're really indispensible for getting a good grounding in the issues and solutions Java provides.


Ping & DNS - my free Android networking tools app
Ram Charan
Greenhorn

Joined: Jun 07, 2008
Posts: 16
That's true. Struts1 action classes are not thread safe. You have to write thread safe action classes(Have only constants as instance variables).
Ulf Dittmer
Marshal

Joined: Mar 22, 2005
Posts: 41095
    
  44
You have to write thread safe action classes (Have only constants as instance variables).

While that approach is sufficient for achieving thread-safety, it's not a necessary. The crucial aspect is that access to shared mutable state must be guarded. There's nothing wrong with using instance variable in servlets or Struts 1 actions, as long as they are read-only, or access to them is properly synchronized.

Note that there are other potential sources of concurrency problems besides instance variables, like sessions and context attributes.
David Newton
Author
Rancher

Joined: Sep 29, 2008
Posts: 12617

This is one of those interview questions where I end up asking the interviewer more questions than s/he asked me in order to be able to actually answer their original question, because as asked, it's a little misleading. They may just be looking for the canonical answer, which in general, makes me not want to work for them.
 
I agree. Here's the link: http://aspose.com/file-tools
 
subject: Is Struts ThreadSafe
 
Similar Threads
is servlet doGet and doPost method are threadsafe?
Dynamically specifying the size of an Array
Is Struts Action class Thread Safe?
Doubt in ThreadSafety
Struts Thread safe