diff --git a/spring-web/src/main/java/org/springframework/http/converter/ResourceHttpMessageConverter.java b/spring-web/src/main/java/org/springframework/http/converter/ResourceHttpMessageConverter.java
index 8173371248..386ca52e36 100644
--- a/spring-web/src/main/java/org/springframework/http/converter/ResourceHttpMessageConverter.java
+++ b/spring-web/src/main/java/org/springframework/http/converter/ResourceHttpMessageConverter.java
@@ -138,6 +138,9 @@ public class ResourceHttpMessageConverter extends AbstractHttpMessageConverter<R
 		}
 
 		public static MediaType getMediaType(Resource resource) {
+			if(resource.getFilename() == null) {
+				return null;
+			}
 			String mediaType = fileTypeMap.getContentType(resource.getFilename());
 			return (StringUtils.hasText(mediaType) ? MediaType.parseMediaType(mediaType) : null);
 		}
diff --git a/spring-web/src/test/java/org/springframework/http/converter/ResourceHttpMessageConverterTests.java b/spring-web/src/test/java/org/springframework/http/converter/ResourceHttpMessageConverterTests.java
index 8d8f38516b..f8c60a94b4 100644
--- a/spring-web/src/test/java/org/springframework/http/converter/ResourceHttpMessageConverterTests.java
+++ b/spring-web/src/test/java/org/springframework/http/converter/ResourceHttpMessageConverterTests.java
@@ -17,11 +17,11 @@
 package org.springframework.http.converter;
 
 import java.io.IOException;
+import java.util.Arrays;
 
-import static org.junit.Assert.*;
 import org.junit.Before;
 import org.junit.Test;
-
+import org.springframework.core.io.ByteArrayResource;
 import org.springframework.core.io.ClassPathResource;
 import org.springframework.core.io.Resource;
 import org.springframework.http.MediaType;
@@ -29,6 +29,8 @@ import org.springframework.http.MockHttpInputMessage;
 import org.springframework.http.MockHttpOutputMessage;
 import org.springframework.util.FileCopyUtils;
 
+import static org.junit.Assert.*;
+
 /**
  * @author Arjen Poutsma
  */
@@ -70,4 +72,15 @@ public class ResourceHttpMessageConverterTests {
 		assertEquals("Invalid content-length", body.getFile().length(), outputMessage.getHeaders().getContentLength());
 	}
 
+	// SPR-10848
+
+	@Test
+	public void writeByteArrayNullMediaType() throws IOException {
+		MockHttpOutputMessage outputMessage = new MockHttpOutputMessage();
+		byte[] byteArray = {1, 2, 3};
+		Resource body = new ByteArrayResource(byteArray);
+		converter.write(body, null, outputMessage);
+		assertTrue(Arrays.equals(byteArray, outputMessage.getBodyAsBytes()));
+	}
+
 }