ResponseEntity headers builder casts body to any type

Issue: SPR-14939

spring-web/src/main/java/org/springframework/http/ResponseEntity.java

@@ -381,7 +381,7 @@ public class ResponseEntity<T> extends HttpEntity<T> {
 		 * @return the response entity
 		 * @see BodyBuilder#body(Object)
 		 */
-		ResponseEntity<Void> build();
+		<T> ResponseEntity<T> build();
 	}
 
 
@@ -505,7 +505,7 @@ public class ResponseEntity<T> extends HttpEntity<T> {
 		}
 
 		@Override
-		public ResponseEntity<Void> build() {
+		public <T> ResponseEntity<T> build() {
 			return body(null);
 		}
 

spring-web/src/test/java/org/springframework/http/ResponseEntityTests.java

@@ -96,6 +96,15 @@ public class ResponseEntityTests {
 		assertNull(responseEntity.getBody());
 	}
 
+	@Test // SPR-14939
+	public void acceptedNoBodyWithAlternativeBodyType() throws URISyntaxException {
+		ResponseEntity<String> responseEntity = ResponseEntity.accepted().build();
+
+		assertNotNull(responseEntity);
+		assertEquals(HttpStatus.ACCEPTED, responseEntity.getStatusCode());
+		assertNull(responseEntity.getBody());
+	}
+
 	@Test
 	public void noContent() throws URISyntaxException {
 		ResponseEntity<Void> responseEntity = ResponseEntity.noContent().build();
@@ -203,7 +212,7 @@ public class ResponseEntityTests {
 
 	@Test
 	public void emptyCacheControl() {
-		Integer entity = new Integer(42);
+		Integer entity = 42;
 
 		ResponseEntity<Integer> responseEntity =
 				ResponseEntity.status(HttpStatus.OK)
@@ -218,7 +227,7 @@ public class ResponseEntityTests {
 
 	@Test
 	public void cacheControl() {
-		Integer entity = new Integer(42);
+		Integer entity = 42;
 
 		ResponseEntity<Integer> responseEntity =
 				ResponseEntity.status(HttpStatus.OK)
@@ -236,7 +245,7 @@ public class ResponseEntityTests {
 
 	@Test
 	public void cacheControlNoCache() {
-		Integer entity = new Integer(42);
+		Integer entity = 42;
 
 		ResponseEntity<Integer> responseEntity =
 				ResponseEntity.status(HttpStatus.OK)
@@ -254,7 +263,7 @@ public class ResponseEntityTests {
 
 	@Test
 	public void statusCodeAsInt() {
-		Integer entity = new Integer(42);
+		Integer entity = 42;
 		ResponseEntity<Integer> responseEntity = ResponseEntity.status(200).body(entity);
 
 		assertEquals(200, responseEntity.getStatusCode().value());
@@ -263,7 +272,7 @@ public class ResponseEntityTests {
 
 	@Test
 	public void customStatusCode() {
-		Integer entity = new Integer(42);
+		Integer entity = 42;
 		ResponseEntity<Integer> responseEntity = ResponseEntity.status(299).body(entity);
 
 		assertEquals(299, responseEntity.getStatusCodeValue());