Fix NPE when body is empty. Fixes #12.

spring-cloud-openfeign-core/src/main/java/org/springframework/cloud/openfeign/ribbon/RetryableFeignLoadBalancer.java

@@ -102,7 +102,7 @@ public class RetryableFeignLoadBalancer extends FeignLoadBalancer implements Ser
 				}
 				Response response = request.client().execute(feignRequest, options);
 				if (retryPolicy.retryableStatusCode(response.status())) {
-					byte[] byteArray = StreamUtils.copyToByteArray(response.body().asInputStream());
+					byte[] byteArray = response.body() == null ? new byte[]{} : StreamUtils.copyToByteArray(response.body().asInputStream());
 					response.close();
 					throw new RibbonResponseStatusCodeException(RetryableFeignLoadBalancer.this.clientName, response,
 							byteArray, request.getUri());

spring-cloud-openfeign-core/src/test/java/org/springframework/cloud/openfeign/ribbon/RetryableFeignLoadBalancerTests.java

@@ -76,6 +76,7 @@ import static org.junit.Assert.assertEquals;
 import static org.mockito.Matchers.any;
 import static org.mockito.Matchers.anyBoolean;
 import static org.mockito.Matchers.anyInt;
+import static org.mockito.Matchers.anyObject;
 import static org.mockito.Matchers.eq;
 import static org.mockito.Mockito.doReturn;
 import static org.mockito.Mockito.doThrow;
@@ -241,6 +242,46 @@ public class RetryableFeignLoadBalancerTests {
 		assertEquals(1, backOffPolicy.getCount());
 	}
 
+		@Test
+	public void executeRetryOnStatusCodeWithEmptyBody() throws Exception {
+			int retriesNextServer = 0;
+			when(this.config.get(MaxAutoRetriesNextServer,
+							DEFAULT_MAX_AUTO_RETRIES_NEXT_SERVER)).thenReturn(retriesNextServer);
+			doReturn(new Server("foo", 80)).when(lb).chooseServer(anyObject());
+			RibbonLoadBalancerContext lbContext = new RibbonLoadBalancerContext(lb, config);
+			SpringClientFactory clientFactory = mock(SpringClientFactory.class);
+			IClientConfig config = mock(IClientConfig.class);
+			doReturn(1).when(config).get(eq(CommonClientConfigKey.MaxAutoRetries), anyInt());
+			doReturn(retriesNextServer).when(config).get(eq(CommonClientConfigKey.MaxAutoRetriesNextServer), anyInt());
+			doReturn(true).when(config).get(eq(CommonClientConfigKey.OkToRetryOnAllOperations), eq(false));
+			doReturn(defaultConnectTimeout).when(config).get(eq(CommonClientConfigKey.ConnectTimeout));
+			doReturn(defaultReadTimeout).when(config).get(eq(CommonClientConfigKey.ReadTimeout));
+			doReturn("404").when(config).getPropertyAsString(eq(RibbonLoadBalancedRetryPolicy.RETRYABLE_STATUS_CODES),eq(""));
+			doReturn(config).when(clientFactory).getClientConfig(eq("default"));
+			doReturn(lbContext).when(clientFactory).getLoadBalancerContext(any(String.class));
+			MyBackOffPolicy backOffPolicy = new MyBackOffPolicy();
+			RibbonLoadBalancedRetryFactory loadBalancedRetryFactory = new RibbonLoadBalancedRetryFactory(clientFactory){
+				@Override
+				public BackOffPolicy createBackOffPolicy(String service) {
+					return backOffPolicy;
+				}
+			};
+			HttpRequest springRequest = mock(HttpRequest.class);
+			Request feignRequest = Request.create("GET", "http://foo", new HashMap<String, Collection<String>>(),
+							new byte[]{}, StandardCharsets.UTF_8);
+			Client client = mock(Client.class);
+			FeignLoadBalancer.RibbonRequest request = new FeignLoadBalancer.RibbonRequest(client, feignRequest, new URI("http://foo"));
+			Response response = Response.builder().status(404).headers(new HashMap<String, Collection<String>>()).build();
+			Response fourOFourResponse = Response.builder().status(404).headers(new HashMap<String, Collection<String>>()).build();
+			doReturn(fourOFourResponse).doReturn(response).when(client).execute(any(Request.class), any(Request.Options.class));
+			RetryableFeignLoadBalancer feignLb = new RetryableFeignLoadBalancer(lb, config, inspector, loadBalancedRetryFactory);
+			FeignLoadBalancer.RibbonResponse ribbonResponse = feignLb.execute(request, null);
+			assertEquals(404, ribbonResponse.toResponse().status());
+			assertEquals(new Integer(0), ribbonResponse.toResponse().body().length());
+			verify(client, times(2)).execute(any(Request.class), any(Request.Options.class));
+			assertEquals(1, backOffPolicy.getCount());
+	}
+
 	@Test
 	public void getRequestSpecificRetryHandler() throws Exception {
 		RibbonLoadBalancerContext lbContext = new RibbonLoadBalancerContext(lb, config);