diff --git a/core/src/main/java/org/elasticsearch/index/similarity/SimilarityLookupService.java b/core/src/main/java/org/elasticsearch/index/similarity/SimilarityLookupService.java
index 8b8b68812cb..903f0ea4039 100644
--- a/core/src/main/java/org/elasticsearch/index/similarity/SimilarityLookupService.java
+++ b/core/src/main/java/org/elasticsearch/index/similarity/SimilarityLookupService.java
@@ -19,16 +19,18 @@
 
 package org.elasticsearch.index.similarity;
 
-import com.google.common.collect.ImmutableMap;
-import org.elasticsearch.common.collect.MapBuilder;
 import org.elasticsearch.common.inject.Inject;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.index.AbstractIndexComponent;
 import org.elasticsearch.index.Index;
 import org.elasticsearch.index.settings.IndexSettings;
 
+import java.util.HashMap;
 import java.util.Map;
 
+import static java.util.Collections.emptyMap;
+import static java.util.Collections.unmodifiableMap;
+
 /**
  * Service for looking up configured {@link SimilarityProvider} implementations by name.
  * <p>
@@ -39,17 +41,17 @@ public class SimilarityLookupService extends AbstractIndexComponent {
 
     public final static String DEFAULT_SIMILARITY = "default";
 
-    private final ImmutableMap<String, SimilarityProvider> similarities;
+    private final Map<String, SimilarityProvider> similarities;
 
     public SimilarityLookupService(Index index, Settings indexSettings) {
-        this(index, indexSettings, ImmutableMap.<String, SimilarityProvider.Factory>of());
+        this(index, indexSettings, emptyMap());
     }
 
     @Inject
     public SimilarityLookupService(Index index, @IndexSettings Settings indexSettings, Map<String, SimilarityProvider.Factory> similarities) {
         super(index, indexSettings);
 
-        MapBuilder<String, SimilarityProvider> providers = MapBuilder.newMapBuilder();
+        Map<String, SimilarityProvider> providers = new HashMap<>();
 
         Map<String, Settings> similaritySettings = indexSettings.getGroups(SimilarityModule.SIMILARITY_SETTINGS_PREFIX);
         for (Map.Entry<String, SimilarityProvider.Factory> entry : similarities.entrySet()) {
@@ -70,7 +72,7 @@ public class SimilarityLookupService extends AbstractIndexComponent {
             }
         }
 
-        this.similarities = providers.immutableMap();
+        this.similarities = unmodifiableMap(providers);
     }
 
     /**
diff --git a/core/src/main/java/org/elasticsearch/search/aggregations/AggregationStreams.java b/core/src/main/java/org/elasticsearch/search/aggregations/AggregationStreams.java
index 97985f3c06e..f4715495c0a 100644
--- a/core/src/main/java/org/elasticsearch/search/aggregations/AggregationStreams.java
+++ b/core/src/main/java/org/elasticsearch/search/aggregations/AggregationStreams.java
@@ -18,20 +18,19 @@
  */
 package org.elasticsearch.search.aggregations;
 
-import com.google.common.collect.ImmutableMap;
 import org.elasticsearch.common.bytes.BytesReference;
-import org.elasticsearch.common.collect.MapBuilder;
+import org.elasticsearch.common.collect.CopyOnWriteHashMap;
 import org.elasticsearch.common.io.stream.StreamInput;
 
 import java.io.IOException;
+import java.util.Map;
 
 /**
  * A registry for all the dedicated streams in the aggregation module. This is to support dynamic addAggregation that
  * know how to stream themselves.
  */
 public class AggregationStreams {
-
-    private static ImmutableMap<BytesReference, Stream> streams = ImmutableMap.of();
+    private static Map<BytesReference, Stream> streams = new CopyOnWriteHashMap<>();
 
     /**
      * A stream that knows how to read an aggregation from the input.
@@ -47,11 +46,9 @@ public class AggregationStreams {
      * @param types     The types associated with the streams
      */
     public static synchronized void registerStream(Stream stream, BytesReference... types) {
-        MapBuilder<BytesReference, Stream> uStreams = MapBuilder.newMapBuilder(streams);
         for (BytesReference type : types) {
-            uStreams.put(type, stream);
+            streams.put(type, stream);
         }
-        streams = uStreams.immutableMap();
     }
 
     /**
diff --git a/core/src/main/java/org/elasticsearch/search/aggregations/InternalAggregations.java b/core/src/main/java/org/elasticsearch/search/aggregations/InternalAggregations.java
index 429768055f0..3841030240e 100644
--- a/core/src/main/java/org/elasticsearch/search/aggregations/InternalAggregations.java
+++ b/core/src/main/java/org/elasticsearch/search/aggregations/InternalAggregations.java
@@ -18,7 +18,6 @@
  */
 package org.elasticsearch.search.aggregations;
 
-import com.google.common.collect.ImmutableMap;
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
@@ -37,6 +36,9 @@ import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.stream.Collectors;
+
+import static java.util.Collections.emptyMap;
+import static java.util.Collections.unmodifiableMap;
 /**
  * An internal implementation of {@link Aggregations}.
  */
@@ -46,7 +48,7 @@ public class InternalAggregations implements Aggregations, ToXContent, Streamabl
 
     private List<InternalAggregation> aggregations = Collections.emptyList();
 
-    private Map<String, InternalAggregation> aggregationsAsMap;
+    private Map<String, Aggregation> aggregationsAsMap;
 
     private InternalAggregations() {
     }
@@ -88,13 +90,13 @@ public class InternalAggregations implements Aggregations, ToXContent, Streamabl
     @Override
     public Map<String, Aggregation> getAsMap() {
         if (aggregationsAsMap == null) {
-            Map<String, InternalAggregation> aggregationsAsMap = new HashMap<>();
+            Map<String, InternalAggregation> newAggregationsAsMap = new HashMap<>();
             for (InternalAggregation aggregation : aggregations) {
-                aggregationsAsMap.put(aggregation.getName(), aggregation);
+                newAggregationsAsMap.put(aggregation.getName(), aggregation);
             }
-            this.aggregationsAsMap = aggregationsAsMap;
+            this.aggregationsAsMap = unmodifiableMap(newAggregationsAsMap);
         }
-        return new HashMap<>(aggregationsAsMap);
+        return aggregationsAsMap;
     }
 
     /**
@@ -200,7 +202,7 @@ public class InternalAggregations implements Aggregations, ToXContent, Streamabl
         int size = in.readVInt();
         if (size == 0) {
             aggregations = Collections.emptyList();
-            aggregationsAsMap = ImmutableMap.of();
+            aggregationsAsMap = emptyMap();
         } else {
             aggregations = new ArrayList<>(size);
             for (int i = 0; i < size; i++) {
diff --git a/core/src/main/java/org/elasticsearch/search/aggregations/bucket/BucketStreams.java b/core/src/main/java/org/elasticsearch/search/aggregations/bucket/BucketStreams.java
index aa489e064ed..4567547dac8 100644
--- a/core/src/main/java/org/elasticsearch/search/aggregations/bucket/BucketStreams.java
+++ b/core/src/main/java/org/elasticsearch/search/aggregations/bucket/BucketStreams.java
@@ -19,16 +19,15 @@
 
 package org.elasticsearch.search.aggregations.bucket;
 
-import com.google.common.collect.ImmutableMap;
 import org.elasticsearch.common.bytes.BytesReference;
-import org.elasticsearch.common.collect.MapBuilder;
+import org.elasticsearch.common.collect.CopyOnWriteHashMap;
 import org.elasticsearch.common.io.stream.StreamInput;
 
 import java.io.IOException;
+import java.util.Map;
 
 public class BucketStreams {
-
-    private static ImmutableMap<BytesReference, Stream> STREAMS = ImmutableMap.of();
+    private static final Map<BytesReference, Stream> streams = new CopyOnWriteHashMap<>();
 
     /**
      * A stream that knows how to read a bucket from the input.
@@ -45,11 +44,9 @@ public class BucketStreams {
      * @param types     The types associated with the streams
      */
     public static synchronized void registerStream(Stream stream, BytesReference... types) {
-        MapBuilder<BytesReference, Stream> uStreams = MapBuilder.newMapBuilder(STREAMS);
         for (BytesReference type : types) {
-            uStreams.put(type, stream);
+            streams.put(type, stream);
         }
-        STREAMS = uStreams.immutableMap();
     }
 
     /**
@@ -59,7 +56,7 @@ public class BucketStreams {
      * @return  The associated stream
      */
     public static Stream stream(BytesReference type) {
-        return STREAMS.get(type);
+        return streams.get(type);
     }
 
 }
diff --git a/core/src/main/java/org/elasticsearch/search/aggregations/pipeline/PipelineAggregatorStreams.java b/core/src/main/java/org/elasticsearch/search/aggregations/pipeline/PipelineAggregatorStreams.java
index 71046092879..5b27569d8a7 100644
--- a/core/src/main/java/org/elasticsearch/search/aggregations/pipeline/PipelineAggregatorStreams.java
+++ b/core/src/main/java/org/elasticsearch/search/aggregations/pipeline/PipelineAggregatorStreams.java
@@ -19,21 +19,18 @@
 package org.elasticsearch.search.aggregations.pipeline;
 
 import org.elasticsearch.common.bytes.BytesReference;
+import org.elasticsearch.common.collect.CopyOnWriteHashMap;
 import org.elasticsearch.common.io.stream.StreamInput;
 
 import java.io.IOException;
-import java.util.HashMap;
 import java.util.Map;
 
-import static java.util.Collections.emptyMap;
-import static java.util.Collections.unmodifiableMap;
-
 /**
  * A registry for all the dedicated streams in the aggregation module. This is to support dynamic addAggregation that
  * know how to stream themselves.
  */
 public class PipelineAggregatorStreams {
-    private static Map<BytesReference, Stream> streams = emptyMap();
+    private static Map<BytesReference, Stream> streams = new CopyOnWriteHashMap<>();
 
     /**
      * A stream that knows how to read an aggregation from the input.
@@ -49,11 +46,9 @@ public class PipelineAggregatorStreams {
      * @param types     The types associated with the streams
      */
     public static synchronized void registerStream(Stream stream, BytesReference... types) {
-        Map<BytesReference, Stream> newStreams = new HashMap<>(streams);
         for (BytesReference type : types) {
-            newStreams.put(type, stream);
+            streams.put(type, stream);
         }
-        streams = unmodifiableMap(newStreams);
     }
 
     /**