[GSS](7.3.z) EAP Undertow Transfer Encoding : chunked setting does not set chunk size and chunk trailer marks

We have attached an example Rest WS to reproduce the issue. First update your standalone.xml to display the Request and Response <subsystem xmlns= "urn:jboss:domain:undertow:7.0" default -server= " default -server" default -virtual-host= " default -host" default -servlet-container= " default " instance-id= "cjde_worker01" default -security-domain= "other" > <buffer-cache name= " default " /> <server name= " default -server" > ........................... <host name= " default -host" alias= "localhost" > <filter-ref name= "proxy-setup" priority= "1" /> <filter-ref name= "proxy-peer-address" priority= "10" /> ..................... <access-log pattern= "%h %l %u %t &quot;%r&quot; %s %b &quot;%{i,Referer}&quot; &quot;%{i,User-Agent}&quot; Cookie: &quot;%{i,COOKIE}&quot; Set-Cookie: &quot;%{o,SET-COOKIE}&quot; SessionID: %S Thread : &quot;%I&quot; TimeTaken: %T" /> <filter-ref name= "server-header" /> <filter-ref name= "x-powered-by-header" /> <filter-ref name= "requestDumperExpression" /> .................. </host> </server> <servlet-container name= " default " > ........... </servlet-container> <filters> ......................... <response-header name= "server-header" header-name= "Server" header-value= "JBoss-EAP/7" /> <response-header name= "x-powered-by-header" header-name= "X-Powered-By" header-value= "Undertow/1" /> <expression-filter name= "requestDumperExpression" expression= "dump-request" /> .................. </filters> </subsystem> Then build and run the deployed WS running http://localhost:8080/demo/api/one/getData/10 This will run successfully and no Transfer Encoding chunked is set by undertow http://localhost:8080/demo/api/one/getData/16 This will run successfully and not Transfer Encoding chunked is set. by undertow Transfer Encoding : chunked is set but no chunk size or trailers are set. You can capture the network packets and examine. ----------------------------REQUEST--------------------------- URI=/demo/api/one/getData/16 characterEncoding= null contentLength=-1 contentType= null header=Accept=text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9 header=Accept-Language=en-US,en;q=0.9 header=Accept-Encoding=gzip, deflate, br header=Sec-Fetch-Mode=navigate header=User-Agent=Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.79 Safari/537.36 header=Sec-Fetch-User=?1 header=Connection=keep-alive header=Sec-Fetch-Site=none header=Upgrade-Insecure-Requests=1 header=Host=localhost:8080 locale=[en_US, en] method=GET protocol=HTTP/1.1 queryString= remoteAddr=/127.0.0.1:47194 remoteHost=pwere.remote.csb scheme=http host=localhost:8080 serverPort=8080 isSecure= false --------------------------RESPONSE-------------------------- contentLength=-1 contentType=text/html;charset=UTF-8 header=Connection=keep-alive header=X-Powered-By=Undertow/1 header=Server=JBoss-EAP/7 header=Transfer-Encoding=chunked header=Content-Type=text/html;charset=UTF-8 header=Date=Tue, 07 Jan 2020 19:26:26 GMT status=200 ============================================================== Request URL: http: //localhost:8080/demo/api/one/getData/16 Request Method: GET Status Code: 200 OK Remote Address: 127.0.0.1:8080 Referrer Policy: no-referrer-when-downgrade Connection: keep-alive Content-Type: text/html;charset=UTF-8 Date: Tue, 07 Jan 2020 19:26:26 GMT Server: JBoss-EAP/7 Transfer-Encoding: chunked X-Powered-By: Undertow/1 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9 Accept-Encoding: gzip, deflate, br Accept-Language: en-US,en;q=0.9 Connection: keep-alive Host: localhost:8080 Sec-Fetch-Mode: navigate Sec-Fetch-Site: none Sec-Fetch-User: ?1 Upgrade-Insecure-Requests: 1 User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.79 Safari/537.36