Use InetAddressResolverProvider and add tests (#1354)

This is a backport of 9a02f81 from `master` to `5.0.x`

JAVA-5390

Author: stIncMale

driver-core/src/main/com/mongodb/internal/connection/ServerAddressHelper.java

@@ -21,17 +21,27 @@
 import com.mongodb.MongoSocketException;
 import com.mongodb.ServerAddress;
 import com.mongodb.UnixServerAddress;
+import com.mongodb.lang.Nullable;
 import com.mongodb.spi.dns.InetAddressResolver;
+import com.mongodb.spi.dns.InetAddressResolverProvider;
 
 import java.net.InetSocketAddress;
 import java.net.UnknownHostException;
 import java.util.List;
+import java.util.ServiceLoader;
 import java.util.stream.Collectors;
+import java.util.stream.StreamSupport;
 
 /**
  * <p>This class is not part of the public API and may be removed or changed at any time</p>
  */
 public final class ServerAddressHelper {
+    @Nullable
+    private static final InetAddressResolver LOCATED_INET_ADDRESS_RESOLVER = StreamSupport.stream(
+            ServiceLoader.load(InetAddressResolverProvider.class).spliterator(), false)
+            .findFirst()
+            .map(InetAddressResolverProvider::create)
+            .orElse(null);
 
     public static ServerAddress createServerAddress(final String host) {
         return createServerAddress(host, ServerAddress.defaultPort());
@@ -46,8 +56,14 @@ public static ServerAddress createServerAddress(final String host, final int por
     }
 
     public static InetAddressResolver getInetAddressResolver(final MongoClientSettings settings) {
-        InetAddressResolver inetAddressResolver = settings.getInetAddressResolver();
-        return inetAddressResolver == null ? new DefaultInetAddressResolver() : inetAddressResolver;
+        InetAddressResolver explicitInetAddressResolver = settings.getInetAddressResolver();
+        if (explicitInetAddressResolver != null) {
+            return explicitInetAddressResolver;
+        } else if (LOCATED_INET_ADDRESS_RESOLVER != null) {
+            return LOCATED_INET_ADDRESS_RESOLVER;
+        } else {
+            return new DefaultInetAddressResolver();
+        }
     }
 
     public static List<InetSocketAddress> getSocketAddresses(final ServerAddress serverAddress, final InetAddressResolver resolver) {

driver-core/src/main/resources/META-INF/native-image/org.mongodb/bson/native-image.properties

@@ -13,4 +13,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
-Args = --initialize-at-run-time=com.mongodb.UnixServerAddress,com.mongodb.internal.connection.SnappyCompressor,org.bson.types.ObjectId,com.mongodb.internal.connection.ClientMetadataHelper
+Args =\
+  --initialize-at-run-time=\
+    com.mongodb.UnixServerAddress,\
+    com.mongodb.internal.connection.SnappyCompressor,\
+    com.mongodb.internal.connection.ClientMetadataHelper,\
+    com.mongodb.internal.connection.ServerAddressHelper

driver-core/src/main/resources/META-INF/native-image/resource-config.json

@@ -0,0 +1,7 @@
+{
+  "resources":{
+  "includes":[{
+    "pattern":"\\QMETA-INF/services/com.mongodb.spi.dns.InetAddressResolverProvider\\E"
+  }]},
+  "bundles":[]
+}

driver-core/src/test/unit/com/mongodb/connection/ServerAddressHelperTest.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright 2008-present MongoDB, Inc.
+ *
+ * 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
+ *
+ *   http://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 com.mongodb.connection;
+
+import com.mongodb.MongoClientSettings;
+import com.mongodb.internal.connection.DefaultInetAddressResolver;
+import com.mongodb.internal.connection.ServerAddressHelper;
+import com.mongodb.spi.dns.InetAddressResolver;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertAll;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertSame;
+
+final class ServerAddressHelperTest {
+    @Test
+    void getInetAddressResolver() {
+        assertAll(
+                () -> assertEquals(
+                        DefaultInetAddressResolver.class,
+                        ServerAddressHelper.getInetAddressResolver(MongoClientSettings.builder().build()).getClass()),
+                () -> {
+                    InetAddressResolver resolver = new DefaultInetAddressResolver();
+                    assertSame(
+                            resolver,
+                            ServerAddressHelper.getInetAddressResolver(MongoClientSettings.builder().inetAddressResolver(resolver).build()));
+                }
+        );
+    }
+}