1. Extract helloworld-rs-matrixparam.zip and copy "helloworld-rs-matrixparam" folder under JBoss EAP 7.4 QuickStarts folder because this depends on the top-level pom.xml of the QuickStart. 2. Build with Maven mvn clean package 3. Deploy the generated helloworld-rs.war by copying it into "$JBOSS_HOME/standalone/deployments/" directory. 4. Start JBoss EAP 7 5. Execute the following curl to send matrix parameters: $ curl "http: //localhost:8080/helloworld-rs/ rest /matrix/example;foo=bar;hoge=fuga;test=test;" Matrix Param List:<br/> Path: example, Matrix Params {test=[test], hoge=[fuga], foo=[bar]}<br/> This can get the expected result. The server can receive 3 matrix parameters "foo=bar", "hoge=fuga" and "test=test". 6. Execute the reproducible test client TestClient.java included in the attached helloworld-rs-matrixparam.zip. The client sends the same matrix parameters, but it calls flush() in the middle of writing HTTP path matrix parameters. So, request packets are separated between the path matrix parameter. $ cat TestClient.java ///usr/bin/env jbang "$0" "$@" ; exit $? import static java.lang. System .*; import java.io.*; import java.net.*; import java.util.*; public class TestClient { private static final String CRLF = "\r\n" ; public static void main( String ... args) throws IOException { Socket socket = new Socket( "127.0.0.1" , 8080); OutputStreamWriter out = new OutputStreamWriter(socket.getOutputStream()); // reproduce the issue by flushing request in the middle of http request path parameter out.write( "GET" ); out.write( " " ); out.write( "/helloworld-rs/ rest /matrix/example;" ); out.write( "foo=bar;" ); out.write( "hoge=fu" ); out.flush(); sleep(100); out.write( "ga;" ); out.write( "test=te" ); out.flush(); sleep(100); out.write( "st;" ); out.write( " HTTP/1.1" ); out.write(CRLF); // end of http request line out.write( "User-Agent: TestClient" + CRLF); out.write( "Host: 127.0.0.1:8080" + CRLF); out.write(CRLF); out.flush(); try (BufferedReader br = new BufferedReader( new InputStreamReader(socket.getInputStream()));) { System .out.println( "response from server:" ); br.lines().forEach(text -> { System .out.println(text); }); } } private static void sleep( long millis) { try { Thread .sleep(millis); } catch (InterruptedException e) { e.printStackTrace(); } } } $ javac TestClient.java $ java TestClient response from server: HTTP/1.1 200 OK Connection: keep-alive Content-Type: application/octet-stream Content-Length: 115 Date: Thu, 05 Jan 2023 06:18:56 GMT Matrix Param List:<br/> Path: example, Matrix Params {st=[ null ], test=[te], hoge=[fu], foo=[bar], ga=[ null ]}<br/> This cannot get the expected result. The server cannot receive 3 matrix parameters "foo=bar", "hoge=fuga" and "test=test" correctly. Because path parameters are processed as "foo=bar;hoge=fu;ga;test=te;st;" with unwanted semicolons in the parameter. Also, you can see the following request line with unwanted semicolons in the access log entry. "GET /helloworld-rs/ rest /matrix/example;foo=bar;hoge=fu;ga;test=te;st; HTTP/1.1"