JAVA ASYNC HTTP CLIENT CODE
JAVA ASYNC HTTP CLIENT FREE

This thread is responsible for executing this assigned task and respond to clients by tomcat connections.

Application assigning this task into another thread by CompletableFuture.

Tomcat server passing requests into applications after getting calls from clients.

That mean’s it is separate from the tomcat thread, and this thread is from Spring. It is handling under onPool-worker-2 the thread.

On last 2 lines of the log is for CompletableFuture part.

From the first 2 lines of the log, it realized that it is releasing before execution of processRequest method part that is under CompletableFuture part.

This thread is from non-blocking IO, and it is from the embedded server. It was also showing requests received and servlet thread released.

The first and second line of log is showing under nio-8080-exec-8 thread.

JAVA ASYNC HTTP CLIENT CODE

To overcome this issue, you may check the below code using. To know details about the terms CompletableFuture, you may check this article CompletableFuture for Asynchronous Programming

JAVA ASYNC HTTP CLIENT FREE

Today we will discuss using CompletableFuture how can we write the asynchronous REST API to make the tomcat free to overcome the thread overflow problem? In this case, clients will face heavy delays during API calls. Here, tomcat has bt default 200 thread so that it could serve a max of 200 requests at a time. If API takes a long time, then that thread waits for its response.This thread waits until the request is served. Now server passes that request into the application, which means the server assigns a new thread into that request and passes this request into the application.If the server currently exceeds the max thread value, then the request waits into the queue. Tomcat server has its internal server configuration like maxThreads, maxConnections Etc. The request comes to the tomcat server with a listening port.

How synchronous applications create problems?įor synchronous applications, what problem create during the request process? Let's figure out the problem. To overcome this thread management problem, we can use asynchronous programming.Īccording to, the definition of asynchronous programming isĪsynchronous programming is a means of parallel programming in which a unit of work runs separately from the main application thread and notifies the calling thread of its completion, failure or progress. The default value is 100.įor a high traffic application, If a request takes much time or takes a long time to serve, it will create a huge problem. The default value for NIO/NIO2 mode is 10,000 and APR/Native is 8,192.Īnother metrics is acceptCount, which represents the maximum number of TCP requests that can wait in a queue at the OS level when there are no worker threads available. Any additional incoming connections will be placed in a queue until a thread becomes available. There are other metrics, maxConnections, representing the total number of concurrent connections that the server will accept and process. For the Tomcat server, its default number of threads maxThreads is 200, representing the maximum number of concurrent threads allowed to run at any given time. Each server can open a limited number of threads, and if that number exceeds, then new clients request will store in the request queue of that server. This thread waits and is appointed until requests are served to that client. You can simply block the calling thread to get the response.Image Credit - During an API call from a client, the server creates and assigns a thread of that request. StringPart Dealing with Responses Blocking on the FutureĮxecute methods return a.Use the addBodyPart method to add a multipart part to the request. Have a look at FeedableBodyGenerator if you're looking for a way to pass requests chunks on the fly. .generator.BodyGeneratorīodyGenerator is a generic abstraction that let you create request bodies on the fly.Use the setBody method to add a body to the request. executeRequest( request) Setting Request Body

build() įuture whenResponse = asyncHttpClient. bound Future whenResponse = asyncHttpClient.

Java async http client