Remove use of com.google.common.collect.Maps

This commit removes all uses of com.google.common.collect.Maps. This is
one of many steps in the eventual removal of Guava as a dependency.

Relates elastic/elasticsearchelastic/elasticsearch#13224

Original commit: elastic/x-pack-elasticsearch@3708fc0c60

shield/src/main/java/org/elasticsearch/shield/transport/ShieldServerTransportService.java

@@ -5,7 +5,6 @@
  */
 package org.elasticsearch.shield.transport;
 
-import com.google.common.collect.Maps;
 import org.elasticsearch.cluster.node.DiscoveryNode;
 import org.elasticsearch.common.inject.Inject;
 import org.elasticsearch.common.settings.Settings;
@@ -19,6 +18,7 @@ import org.elasticsearch.transport.*;
 import org.elasticsearch.transport.netty.NettyTransport;
 
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.Map;
 import java.util.concurrent.Callable;
 
@@ -80,7 +80,7 @@ public class ShieldServerTransportService extends TransportService {
         }
 
         Map<String, Settings> profileSettingsMap = settings.getGroups("transport.profiles.", true);
-        Map<String, ServerTransportFilter> profileFilters = Maps.newHashMapWithExpectedSize(profileSettingsMap.size() + 1);
+        Map<String, ServerTransportFilter> profileFilters = new HashMap<>(profileSettingsMap.size() + 1);
 
         for (Map.Entry<String, Settings> entry : profileSettingsMap.entrySet()) {
             Settings profileSettings = entry.getValue();

shield/src/main/java/org/elasticsearch/shield/transport/filter/IPFilter.java

@@ -7,7 +7,6 @@ package org.elasticsearch.shield.transport.filter;
 
 import com.carrotsearch.hppc.ObjectObjectHashMap;
 import com.google.common.collect.ImmutableMap;
-import com.google.common.collect.Maps;
 import com.google.common.collect.ObjectArrays;
 import org.elasticsearch.ElasticsearchException;
 import org.elasticsearch.common.collect.HppcMaps;
@@ -24,7 +23,6 @@ import org.elasticsearch.shield.audit.AuditTrail;
 import org.elasticsearch.transport.Transport;
 
 import java.net.InetAddress;
-import java.net.UnknownHostException;
 import java.util.*;
 
 public class IPFilter extends AbstractLifecycleComponent<IPFilter> {
@@ -143,7 +141,7 @@ public class IPFilter extends AbstractLifecycleComponent<IPFilter> {
             return Collections.EMPTY_MAP;
         }
 
-        Map<String, ShieldIpFilterRule[]> profileRules = Maps.newHashMap();
+        Map<String, ShieldIpFilterRule[]> profileRules = new HashMap<>();
 
         if (isHttpFilterEnabled && httpServerTransport != null && httpServerTransport.lifecycleState() == Lifecycle.State.STARTED) {
             InetAddress localAddress = ((InetSocketTransportAddress) this.httpServerTransport.boundAddress().boundAddress()).address().getAddress();

shield/src/test/java/org/elasticsearch/integration/AbstractPrivilegeTestCase.java

@@ -5,8 +5,6 @@
  */
 package org.elasticsearch.integration;
 
-import com.google.common.collect.Maps;
-
 import org.apache.http.impl.client.CloseableHttpClient;
 import org.apache.http.impl.client.HttpClients;
 import org.elasticsearch.http.HttpServerTransport;
@@ -19,6 +17,7 @@ import org.elasticsearch.test.rest.client.http.HttpResponse;
 import org.junit.After;
 
 import java.io.IOException;
+import java.util.HashMap;
 import java.util.Locale;
 import java.util.Map;
 
@@ -45,19 +44,19 @@ public abstract class AbstractPrivilegeTestCase extends ShieldIntegTestCase {
     }
 
     protected void assertAccessIsAllowed(String user, String method, String uri, String body) throws IOException {
-        assertAccessIsAllowed(user, method, uri, body, Maps.<String,String>newHashMap());
+        assertAccessIsAllowed(user, method, uri, body, new HashMap<>());
     }
 
     protected void assertAccessIsAllowed(String user, String method, String uri) throws IOException {
-        assertAccessIsAllowed(user, method, uri, null, Maps.<String,String>newHashMap());
+        assertAccessIsAllowed(user, method, uri, null, new HashMap<>());
     }
 
     protected void assertAccessIsDenied(String user, String method, String uri, String body) throws IOException {
-        assertAccessIsDenied(user, method, uri, body, Maps.<String,String>newHashMap());
+        assertAccessIsDenied(user, method, uri, body, new HashMap<>());
     }
 
     protected void assertAccessIsDenied(String user, String method, String uri) throws IOException {
-        assertAccessIsDenied(user, method, uri, null, Maps.<String,String>newHashMap());
+        assertAccessIsDenied(user, method, uri, null, new HashMap<>());
     }
 
     protected void assertAccessIsDenied(String user, String method, String uri, String body, Map<String, String> params) throws IOException {

shield/src/test/java/org/elasticsearch/integration/IndexPrivilegeTests.java

@@ -5,7 +5,6 @@
  */
 package org.elasticsearch.integration;
 
-import com.google.common.collect.Maps;
 import com.google.common.collect.ImmutableMap;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.node.Node;
@@ -13,6 +12,7 @@ import org.elasticsearch.test.rest.client.http.HttpResponse;
 import org.junit.Before;
 import org.junit.Test;
 
+import java.util.HashMap;
 import java.util.Locale;
 
 import static org.hamcrest.Matchers.is;
@@ -320,7 +320,7 @@ public class IndexPrivilegeTests extends AbstractPrivilegeTestCase {
 
     @Test
     public void testThatUnknownUserIsRejectedProperly() throws Exception {
-        HttpResponse response = executeRequest("idonotexist", "GET", "/", null, Maps.<String,String>newHashMap());
+        HttpResponse response = executeRequest("idonotexist", "GET", "/", null, new HashMap<>());
         assertThat(response.getStatusCode(), is(401));
     }