diff a/test/jdk/java/net/httpclient/MultipartBodyPublisherRawTest.java b/test/jdk/java/net/httpclient/MultipartBodyPublisherRawTest.java
--- /dev/null
+++ b/test/jdk/java/net/httpclient/MultipartBodyPublisherRawTest.java
@@ -0,0 +1,34 @@
+
+import java.net.URI;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse.BodyHandlers;
+import java.nio.file.Path;
+
+public class MultipartBodyPublisherRawTest {
+
+    static final String CRLF = "\r\n";
+    static final String BOUNDARY = "gc0p4Jq0M2Yt08jU534c0p";
+    static final String BOUNDARY_START = "--";
+    static final String BOUNDARY_END = "--";
+
+    public static void main(String... args) throws Exception {
+
+        // # using raw concat only !
+        var publisher = HttpRequest.BodyPublishers.concat(
+                // preamble
+                HttpRequest.BodyPublishers.ofString(CRLF + BOUNDARY_START + BOUNDARY + CRLF + "Content-Type: text/plain; charset=us-ascii" + CRLF),
+                HttpRequest.BodyPublishers.ofFile(Path.of("/tmp/xxyy")),
+                HttpRequest.BodyPublishers.ofString(CRLF + BOUNDARY_START + BOUNDARY + BOUNDARY_END)
+                // epilogue
+        );
+
+        var client = HttpClient.newHttpClient();
+        var request = HttpRequest.newBuilder()
+                .uri(URI.create("http://foo.com/"))
+                .header("Content-Type", "multipart/mixed; boundary=" + BOUNDARY)
+                .POST(publisher)
+                .build();
+        client.send(request, BodyHandlers.ofString());
+    }
+}