diff --git a/core/src/main/java/org/elasticsearch/cluster/node/DiscoveryNode.java b/core/src/main/java/org/elasticsearch/cluster/node/DiscoveryNode.java
index 3eea37e2c89..0e8435d0f8e 100644
--- a/core/src/main/java/org/elasticsearch/cluster/node/DiscoveryNode.java
+++ b/core/src/main/java/org/elasticsearch/cluster/node/DiscoveryNode.java
@@ -198,7 +198,7 @@ public class DiscoveryNode implements Writeable, ToXContent {
 
     /** extract node roles from the given settings */
     public static Set<Role> getRolesFromSettings(Settings settings) {
-        Set<Role> roles = new HashSet<>();
+        Set<Role> roles = EnumSet.noneOf(Role.class);
         if (Node.NODE_INGEST_SETTING.get(settings)) {
             roles.add(Role.INGEST);
         }
diff --git a/core/src/main/java/org/elasticsearch/cluster/routing/allocation/AllocateUnassignedDecision.java b/core/src/main/java/org/elasticsearch/cluster/routing/allocation/AllocateUnassignedDecision.java
index 49b9604e345..decdafd724c 100644
--- a/core/src/main/java/org/elasticsearch/cluster/routing/allocation/AllocateUnassignedDecision.java
+++ b/core/src/main/java/org/elasticsearch/cluster/routing/allocation/AllocateUnassignedDecision.java
@@ -31,7 +31,7 @@ import org.elasticsearch.common.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Collections;
-import java.util.HashMap;
+import java.util.EnumMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
@@ -49,7 +49,7 @@ public class AllocateUnassignedDecision extends AbstractAllocationDecision {
      */
     private static final Map<AllocationStatus, AllocateUnassignedDecision> CACHED_DECISIONS;
     static {
-        Map<AllocationStatus, AllocateUnassignedDecision> cachedDecisions = new HashMap<>();
+        Map<AllocationStatus, AllocateUnassignedDecision> cachedDecisions = new EnumMap<>(AllocationStatus.class);
         cachedDecisions.put(AllocationStatus.FETCHING_SHARD_DATA,
             new AllocateUnassignedDecision(AllocationStatus.FETCHING_SHARD_DATA, null, null, null, false, 0L, 0L));
         cachedDecisions.put(AllocationStatus.NO_VALID_SHARD_COPY,
diff --git a/core/src/main/java/org/elasticsearch/common/settings/SecureSetting.java b/core/src/main/java/org/elasticsearch/common/settings/SecureSetting.java
index 2efb36696c5..e93240b9a32 100644
--- a/core/src/main/java/org/elasticsearch/common/settings/SecureSetting.java
+++ b/core/src/main/java/org/elasticsearch/common/settings/SecureSetting.java
@@ -21,12 +21,9 @@ package org.elasticsearch.common.settings;
 
 import java.io.InputStream;
 import java.security.GeneralSecurityException;
-import java.util.Arrays;
-import java.util.HashSet;
-import java.util.Objects;
+import java.util.EnumSet;
 import java.util.Set;
 
-import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.util.ArrayUtils;
 
 
@@ -36,9 +33,7 @@ import org.elasticsearch.common.util.ArrayUtils;
  * This class allows access to settings from the Elasticsearch keystore.
  */
 public abstract class SecureSetting<T> extends Setting<T> {
-    private static final Set<Property> ALLOWED_PROPERTIES = new HashSet<>(
-        Arrays.asList(Property.Deprecated, Property.Shared)
-    );
+    private static final Set<Property> ALLOWED_PROPERTIES = EnumSet.of(Property.Deprecated, Property.Shared);
 
     private static final Property[] FIXED_PROPERTIES = {
         Property.NodeScope
diff --git a/core/src/main/java/org/elasticsearch/common/unit/TimeValue.java b/core/src/main/java/org/elasticsearch/common/unit/TimeValue.java
index 4ab91aac5b5..4c3344eb9d8 100644
--- a/core/src/main/java/org/elasticsearch/common/unit/TimeValue.java
+++ b/core/src/main/java/org/elasticsearch/common/unit/TimeValue.java
@@ -31,6 +31,7 @@ import org.joda.time.format.PeriodFormatter;
 
 import java.io.IOException;
 import java.util.Collections;
+import java.util.EnumMap;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Locale;
@@ -48,7 +49,7 @@ public class TimeValue implements Writeable, Comparable<TimeValue> {
     private static Map<Byte, TimeUnit> BYTE_TIME_UNIT_MAP;
 
     static {
-        final Map<TimeUnit, Byte> timeUnitByteMap = new HashMap<>();
+        final Map<TimeUnit, Byte> timeUnitByteMap = new EnumMap<>(TimeUnit.class);
         timeUnitByteMap.put(TimeUnit.NANOSECONDS, (byte)0);
         timeUnitByteMap.put(TimeUnit.MICROSECONDS, (byte)1);
         timeUnitByteMap.put(TimeUnit.MILLISECONDS, (byte)2);
diff --git a/core/src/main/java/org/elasticsearch/ingest/IngestDocument.java b/core/src/main/java/org/elasticsearch/ingest/IngestDocument.java
index 02d3988c4a8..fcf49ef6992 100644
--- a/core/src/main/java/org/elasticsearch/ingest/IngestDocument.java
+++ b/core/src/main/java/org/elasticsearch/ingest/IngestDocument.java
@@ -31,6 +31,7 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Base64;
 import java.util.Date;
+import java.util.EnumMap;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -554,7 +555,7 @@ public final class IngestDocument {
      * Metadata fields that used to be accessible as ordinary top level fields will be removed as part of this call.
      */
     public Map<MetaData, String> extractMetadata() {
-        Map<MetaData, String> metadataMap = new HashMap<>();
+        Map<MetaData, String> metadataMap = new EnumMap<>(MetaData.class);
         for (MetaData metaData : MetaData.values()) {
             metadataMap.put(metaData, cast(metaData.getFieldName(), sourceAndMetadata.remove(metaData.getFieldName()), String.class));
         }
diff --git a/core/src/main/java/org/elasticsearch/script/ScriptSettings.java b/core/src/main/java/org/elasticsearch/script/ScriptSettings.java
index 447097a4884..e4387aa52dd 100644
--- a/core/src/main/java/org/elasticsearch/script/ScriptSettings.java
+++ b/core/src/main/java/org/elasticsearch/script/ScriptSettings.java
@@ -25,6 +25,7 @@ import org.elasticsearch.common.settings.Settings;
 
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.EnumMap;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -35,7 +36,7 @@ public class ScriptSettings {
     private static final Map<ScriptType, Setting<Boolean>> SCRIPT_TYPE_SETTING_MAP;
 
     static {
-        Map<ScriptType, Setting<Boolean>> scriptTypeSettingMap = new HashMap<>();
+        Map<ScriptType, Setting<Boolean>> scriptTypeSettingMap = new EnumMap<>(ScriptType.class);
         for (ScriptType scriptType : ScriptType.values()) {
             scriptTypeSettingMap.put(scriptType, Setting.boolSetting(
                 ScriptModes.sourceKey(scriptType),
diff --git a/core/src/main/java/org/elasticsearch/search/internal/SearchContext.java b/core/src/main/java/org/elasticsearch/search/internal/SearchContext.java
index 59d3646f18f..ebb2157d981 100644
--- a/core/src/main/java/org/elasticsearch/search/internal/SearchContext.java
+++ b/core/src/main/java/org/elasticsearch/search/internal/SearchContext.java
@@ -63,7 +63,7 @@ import org.elasticsearch.search.sort.SortAndFormats;
 import org.elasticsearch.search.suggest.SuggestionSearchContext;
 
 import java.util.ArrayList;
-import java.util.HashMap;
+import java.util.EnumMap;
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -336,7 +336,7 @@ public abstract class SearchContext extends AbstractRefCounted implements Releas
      */
     public void addReleasable(Releasable releasable, Lifetime lifetime) {
         if (clearables == null) {
-            clearables = new HashMap<>();
+            clearables = new EnumMap<>(Lifetime.class);
         }
         List<Releasable> releasables = clearables.get(lifetime);
         if (releasables == null) {
diff --git a/test/framework/src/main/java/org/elasticsearch/AnalysisFactoryTestCase.java b/test/framework/src/main/java/org/elasticsearch/AnalysisFactoryTestCase.java
index 7f60058788a..d49a1b4cae5 100644
--- a/test/framework/src/main/java/org/elasticsearch/AnalysisFactoryTestCase.java
+++ b/test/framework/src/main/java/org/elasticsearch/AnalysisFactoryTestCase.java
@@ -98,6 +98,7 @@ import org.elasticsearch.indices.analysis.PreBuiltTokenizers;
 import org.elasticsearch.test.ESTestCase;
 
 import java.util.Collection;
+import java.util.EnumMap;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Map;
@@ -152,7 +153,7 @@ public class AnalysisFactoryTestCase extends ESTestCase {
 
     static final Map<PreBuiltTokenizers, Class<?>> PREBUILT_TOKENIZERS;
     static {
-        PREBUILT_TOKENIZERS = new HashMap<>();
+        PREBUILT_TOKENIZERS = new EnumMap<>(PreBuiltTokenizers.class);
         for (PreBuiltTokenizers tokenizer : PreBuiltTokenizers.values()) {
             Class<?> luceneFactoryClazz;
             switch (tokenizer) {
@@ -289,7 +290,7 @@ public class AnalysisFactoryTestCase extends ESTestCase {
 
     static final Map<PreBuiltTokenFilters, Class<?>> PREBUILT_TOKENFILTERS;
     static {
-        PREBUILT_TOKENFILTERS = new HashMap<>();
+        PREBUILT_TOKENFILTERS = new EnumMap<>(PreBuiltTokenFilters.class);
         for (PreBuiltTokenFilters tokenizer : PreBuiltTokenFilters.values()) {
             Class<?> luceneFactoryClazz;
             switch (tokenizer) {
@@ -335,7 +336,7 @@ public class AnalysisFactoryTestCase extends ESTestCase {
 
     static final Map<PreBuiltCharFilters, Class<?>> PREBUILT_CHARFILTERS;
     static {
-        PREBUILT_CHARFILTERS = new HashMap<>();
+        PREBUILT_CHARFILTERS = new EnumMap<>(PreBuiltCharFilters.class);
         for (PreBuiltCharFilters tokenizer : PreBuiltCharFilters.values()) {
             Class<?> luceneFactoryClazz;
             switch (tokenizer) {
diff --git a/test/framework/src/main/java/org/elasticsearch/cluster/ESAllocationTestCase.java b/test/framework/src/main/java/org/elasticsearch/cluster/ESAllocationTestCase.java
index a0cc0130bfc..02f8896be4d 100644
--- a/test/framework/src/main/java/org/elasticsearch/cluster/ESAllocationTestCase.java
+++ b/test/framework/src/main/java/org/elasticsearch/cluster/ESAllocationTestCase.java
@@ -43,7 +43,7 @@ import org.elasticsearch.test.gateway.TestGatewayAllocator;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
-import java.util.HashSet;
+import java.util.EnumSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Random;
@@ -95,7 +95,7 @@ public abstract class ESAllocationTestCase extends ESTestCase {
     }
 
     protected static Set<DiscoveryNode.Role> MASTER_DATA_ROLES =
-            Collections.unmodifiableSet(new HashSet<>(Arrays.asList(DiscoveryNode.Role.MASTER, DiscoveryNode.Role.DATA)));
+            Collections.unmodifiableSet(EnumSet.of(DiscoveryNode.Role.MASTER, DiscoveryNode.Role.DATA));
 
     protected static DiscoveryNode newNode(String nodeId) {
         return newNode(nodeId, Version.CURRENT);
diff --git a/test/framework/src/main/java/org/elasticsearch/test/ClusterServiceUtils.java b/test/framework/src/main/java/org/elasticsearch/test/ClusterServiceUtils.java
index 01f626a1e2b..b2eced6fd35 100644
--- a/test/framework/src/main/java/org/elasticsearch/test/ClusterServiceUtils.java
+++ b/test/framework/src/main/java/org/elasticsearch/test/ClusterServiceUtils.java
@@ -33,7 +33,7 @@ import org.elasticsearch.threadpool.ThreadPool;
 
 import java.util.Arrays;
 import java.util.Collections;
-import java.util.HashSet;
+import java.util.EnumSet;
 import java.util.concurrent.CountDownLatch;
 
 import static junit.framework.TestCase.fail;
@@ -42,7 +42,7 @@ public class ClusterServiceUtils {
 
     public static ClusterService createClusterService(ThreadPool threadPool) {
         DiscoveryNode discoveryNode = new DiscoveryNode("node", ESTestCase.buildNewFakeTransportAddress(), Collections.emptyMap(),
-                                                           new HashSet<>(Arrays.asList(DiscoveryNode.Role.values())),Version.CURRENT);
+                EnumSet.allOf(DiscoveryNode.Role.class), Version.CURRENT);
         return createClusterService(threadPool, discoveryNode);
     }
 
diff --git a/test/framework/src/main/java/org/elasticsearch/test/PosixPermissionsResetter.java b/test/framework/src/main/java/org/elasticsearch/test/PosixPermissionsResetter.java
index a644205bad9..19bea3802f0 100644
--- a/test/framework/src/main/java/org/elasticsearch/test/PosixPermissionsResetter.java
+++ b/test/framework/src/main/java/org/elasticsearch/test/PosixPermissionsResetter.java
@@ -18,6 +18,8 @@
  */
 package org.elasticsearch.test;
 
+import java.util.EnumSet;
+import java.util.Set;
 import org.junit.Assert;
 
 import java.io.IOException;
@@ -25,8 +27,6 @@ import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.attribute.PosixFileAttributeView;
 import java.nio.file.attribute.PosixFilePermission;
-import java.util.HashSet;
-import java.util.Set;
 
 /** Stores the posix attributes for a path and resets them on close. */
 public class PosixPermissionsResetter implements AutoCloseable {
@@ -46,6 +46,6 @@ public class PosixPermissionsResetter implements AutoCloseable {
     }
 
     public Set<PosixFilePermission> getCopyPermissions() {
-        return new HashSet<>(permissions);
+        return EnumSet.copyOf(permissions);
     }
 }