java - Why Californium wait after 65535 records while sending data using CoAP protocol -

i'm using californium api ( https://github.com/eclipse/californium ) send data using coap protocol.

below snippet both client , server.

server :

public class helloworldserver extends coapserver {     /*      * application entry point.      */     public static void main(string[] args) {         try {             // create server             helloworldserver server = new helloworldserver();             server.start();         } catch (socketexception e) {             system.err                     .println("failed initialize server: " + e.getmessage());         }     }      /*      * constructor new hello-world server. here, resources of      * server initialized.      */     public helloworldserver() throws socketexception {         // provide instance of hello-world resource         add(new helloworldresource());     }      /*      * definition of hello-world resource      */     class helloworldresource extends coapresource {         public helloworldresource() {             // set resource identifier             super("helloworld");             // set display name             getattributes().settitle("hello-world resource");         }          @override         public void handleget(coapexchange exchange) {             // respond request             exchange.respond("hello world!");         }          @override         public void handlepost(coapexchange exchange){             //system.out.println("start "+system.currenttimemillis());             exchange.accept();                        //list<string> queries = exchange.getrequestoptions().geturiqueries();         //    system.out.println("text received : "+ exchange.getrequesttext().length());         //    system.out.println("end "+system.currenttimemillis());             exchange.respond("received");           }     } } 

client code :

try {                         long starttime = system.currenttimemillis();             (int = 0; < 1000000; i++) {                 coapclient client = new coapclient(new uri("coap://192.168.15.170:5683/helloworld"));                 coapresponse response = client.post(str, 0);                          }             system.out.println("done");                  } catch (urisyntaxexception e) {             e.printstacktrace();         }catch (exception e) {             e.printstacktrace();         } 

i'm sending 1000000 records while sending first send 65535 records , wait few seconds.after waiting few seconds again starts sending.

system details :

os : win 7 64 bit. ram : 4 gm

why wait after 65535 records?

i gone through californium.coap receives 250 records per second. have added relay of 4 ms.so manage send less 250 records/second.

if sending data different machine same coap server resource, need manage delay accordingly.

coap message id (mid) ranginf 1-65565 only.

also configure californium.properties work.