java - FutureTask call() refer object, result wrong -


i want result 

jsonobject={"key":[2,2,3]} jsonobject={"key":[2,4,3]} jsonobject={"key":[2,4,6]}

but result is

{"key":[2,4,6]} {"key":[2,4,6]} {"key":[2,4,6]}

i dont know what's wrong. please help. thanks!

how change code? object last number.

code is:

public class testfuturetask {     public static void main(string[] args) {         int[] list = {1,2,3};         executorservice executor = executors.newcachedthreadpool();         list<futuretask<string>> futuretasks = new arraylist<>();          for(int i=0;i<list.length;i++){             int[] list1 = list;             list1[i] = list1[i]*2;             jsonobject jsonobject = new jsonobject();             jsonobject.put("key", list1);             futuretasks.add(new futuretask<string>(new queryexecutor(jsonobject)));         }          for(int n=0;n<futuretasks.size();n++){             executor.submit(futuretasks.get(n));         }          for(int n=0;n<futuretasks.size();n++){             try {                 system.out.println(futuretasks.get(n).get());             } catch (interruptedexception e) {                 e.printstacktrace();             } catch (executionexception e) {                 e.printstacktrace();             }             {                 executor.shutdown();             }         }     } }  class queryexecutor implements callable<string> {     private jsonobject jsonobject;     public queryexecutor(jsonobject jsonobject){         system.out.println("jsonobject="+jsonobject);         this.jsonobject = jsonobject;     }     @override     public string call(){         string result = jsonobject.tostring();         return result;     }  }

i think maybe async , method call() refer object problem.

executorservice , futuretask.

as reminder arrays in java objects.

your problem same object referencing see below snippet of code

 int[] list = {1,2,3};  int[] list1 = list;  list1[i] = list1[i]*2;

when update reference list1 list gets updated because point same object internally , hence array passed below call method in furture reference same.

try changing from

int[] list1 = list;

to 

int[] list1 = arrays.copyof(list,list.length);

run , see if meets expectations


Comments

Post a Comment

Popular posts from this blog

Is there a better way to structure post methods in Class Based Views -

i'm using class based views in django , never specify url in ajax calls , omit action parameter in form because know these requests go through post method of class based view. notice view - profile page make many requests depending on user updating on page - post method become convoluted , if/else mess example: def post(self, request, *args, **kwargs): # handle user changing available date if request.post.get('availabledate') != none: self.updateavailabledate(request) return jsonresponse({'result':'success'}) if request.post.get('newprojectname') != none: creative_user = creativeuserprofile.objects.get(id = request.user.id) project = project.create_project(creative_user, request.post['newprojectname']) project.save() return jsonresponse({'projectid': project.id }) if request.post.get('projectimage') != none , request.files['file']: proj...
Read more

performance - Why is XCHG reg, reg a 3 micro-op instruction on modern Intel architectures? -

i'm doing micro-optimization on performance critical part of code , came across sequence of instructions (in at&t syntax): add %rax, %rbx mov %rdx, %rax mov %rbx, %rdx i thought had use case xchg allow me shave instruction , write: add %rbx, %rax xchg %rax, %rdx however, dimay found agner fog's instruction tables , xchg 3 micro-op instruction 2 cycle latency on sandy bridge, ivy bridge, broadwell, haswell , skylake. 3 whole micro-ops , 2 cycles of latency! 3 micro-ops throws off 4-1-1-1 cadence , 2 cycle latency makes worse original in best case since last 2 instructions in original might execute in parallel. now... cpu might breaking instruction micro-ops equivalent to: mov %rax, %tmp mov %rdx, %rax mov %tmp, %rdx where tmp anonymous internal register , suppose last 2 micro-ops run in parallel latency 2 cycles. given register renaming occurs on these micro-architectures, though, doesn't make sense me done way. why wouldn't register renamer ...
Read more

c# - Asp.net web api : redirect unauthorized requst to forbidden page -

im trying redirect unauthorized request forbidden page instead i'm getting forbidden page in response body , how can fix ? here's startup class : app.createperowincontext(storecontext.create); app.createperowincontext<applicationusermanager>(applicationusermanager.create); app.createperowincontext<applicationsigninmanager>(applicationsigninmanager.create); app.usecookieauthentication(new cookieauthenticationoptions { authenticationtype = defaultauthenticationtypes.applicationcookie, expiretimespan = timespan.fromdays(30), }); app.useexternalsignincookie(defaultauthenticationtypes.externalcookie); app.usetwofactorsignincookie(defaultauthenticationtypes.twofactorcookie, timespan.fromminutes(5)); app.usetwofactorrememberbrowsercookie(defaultauthenticationtypes.twofactorrememberbrowsercookie); the method im trying reach : [httpget] [authorize(roles = "admin")] public string getcurrentusername() { return userman...
Read more