#1661 - Prevent IndexOutOfBoundException in WebConverters.

We now skip the registration of the default media type if no hypermedia types are activated in the first place. We previously assumed there'd be at least one media type configuration registered.

src/main/java/org/springframework/hateoas/config/WebConverters.java

@@ -114,7 +114,7 @@ public class WebConverters {
 			converter.registerObjectMappersForType(rootType, map -> map.putAll(mappers));
 		}
 
-		if (!includeGenericJsonTypes) {
+		if (!includeGenericJsonTypes || infos.isEmpty()) {
 			return;
 		}
 

src/test/java/org/springframework/hateoas/config/WebConvertersUnitTests.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2021 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.hateoas.config;
+
+import static org.assertj.core.api.Assertions.*;
+
+import java.util.Collections;
+
+import org.junit.jupiter.api.Test;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+/**
+ * Unit tests for {@link WebConverters}.
+ *
+ * @author Oliver Drotbohm
+ */
+class WebConvertersUnitTests {
+
+	@Test // #1657
+	void augmentsConvertersWithoutHypermediaInformationsRegistered() {
+
+		WebConverters converters = WebConverters.of(new ObjectMapper(), Collections.emptyList());
+
+		assertThatNoException() //
+				.isThrownBy(() -> converters.augmentClient(Collections.emptyList()));
+	}
+}