Reduce allocations due to Jackson serialization. (#12468)

* Reduce allocations due to Jackson serialization.

This patch attacks two sources of allocations during Jackson
serialization:

1) ObjectMapper.writeValue and JsonGenerator.writeObject create a new
   DefaultSerializerProvider instance for each call. It has lots of
   fields and creates pressure on the garbage collector. So, this patch
   adds helper functions in JacksonUtils that enable reuse of
   SerializerProvider objects and updates various call sites to make
   use of this.

2) GroupByQueryToolChest copies the ObjectMapper for every query to
   install a special module that supports backwards compatibility with
   map-based rows. This isn't needed if resultAsArray is set and
   all servers are running Druid 0.16.0 or later. This release was a
   while ago. So, this patch disables backwards compatibility by default,
   which eliminates the need to copy the heavyweight ObjectMapper. The
   patch also introduces a configuration option that allows admins to
   explicitly enable backwards compatibility.

* Add test.

* Update additional call sites and add to forbidden APIs.

codestyle/druid-forbidden-apis.txt

@@ -1,6 +1,8 @@
 com.fasterxml.jackson.databind.ObjectMapper#reader(com.fasterxml.jackson.core.type.TypeReference) @ Use ObjectMapper#readerFor instead
 com.fasterxml.jackson.databind.ObjectMapper#reader(com.fasterxml.jackson.databind.JavaType) @ Use ObjectMapper#readerFor instead
 com.fasterxml.jackson.databind.ObjectMapper#reader(java.lang.Class) @ Use ObjectMapper#readerFor instead
+com.fasterxml.jackson.databind.ObjectMapper#writeValue(com.fasterxml.jackson.core.JsonGenerator, java.lang.Object) @ Use JacksonUtils#writeObjectUsingSerializerProvider to allow SerializerProvider reuse
+com.fasterxml.jackson.core.JsonGenerator#writeObject(java.lang.Object) @ Use JacksonUtils#writeObjectUsingSerializerProvider to allow SerializerProvider reuse
 com.google.common.base.Charsets @ Use java.nio.charset.StandardCharsets instead
 com.google.common.collect.Iterators#emptyIterator() @ Use java.util.Collections#emptyIterator()
 com.google.common.collect.Lists#newArrayList() @ Create java.util.ArrayList directly

core/src/main/java/org/apache/druid/java/util/common/jackson/JacksonUtils.java

@@ -19,9 +19,14 @@
 
 package org.apache.druid.java.util.common.jackson;
 
+import com.fasterxml.jackson.core.JsonGenerator;
 import com.fasterxml.jackson.core.type.TypeReference;
+import com.fasterxml.jackson.databind.JsonMappingException;
+import com.fasterxml.jackson.databind.JsonSerializer;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializerProvider;
 
+import javax.annotation.Nullable;
 import java.io.IOException;
 import java.util.Map;
 
@@ -40,7 +45,9 @@ public final class JacksonUtils
       {
       };
 
-  /** Silences Jackson's {@link IOException}. */
+  /**
+   * Silences Jackson's {@link IOException}.
+   */
   public static <T> T readValue(ObjectMapper mapper, byte[] bytes, Class<T> valueClass)
   {
     try {
@@ -51,6 +58,37 @@ public final class JacksonUtils
     }
   }
 
+  /**
+   * Returns a serializer for a particular class. If you have a {@link SerializerProvider}, this is better than calling
+   * {@link JsonGenerator#writeObject(Object)} or {@link ObjectMapper#writeValue(JsonGenerator, Object)}, because it
+   * avoids re-creating the {@link SerializerProvider} for each serialized object.
+   */
+  public static JsonSerializer<Object> getSerializer(final SerializerProvider serializerProvider, final Class<?> clazz)
+      throws JsonMappingException
+  {
+    // cache = true, property = null because this is what DefaultSerializerProvider.serializeValue would do.
+    return serializerProvider.findTypedValueSerializer(clazz, true, null);
+  }
+
+  /**
+   * Serializes an object using a {@link JsonGenerator}. If you have a {@link SerializerProvider}, this is better than
+   * calling {@link JsonGenerator#writeObject(Object)}, because it avoids re-creating the {@link SerializerProvider}
+   * for each serialized object.
+   */
+  public static void writeObjectUsingSerializerProvider(
+      final JsonGenerator jsonGenerator,
+      final SerializerProvider serializers,
+      @Nullable final Object o
+  ) throws IOException
+  {
+    if (o == null) {
+      jsonGenerator.writeNull();
+    } else {
+      final JsonSerializer<Object> serializer = getSerializer(serializers, o.getClass());
+      serializer.serialize(o, jsonGenerator, serializers);
+    }
+  }
+
   private JacksonUtils()
   {
   }

core/src/test/java/org/apache/druid/common/jackson/JacksonUtilsTest.java

@@ -0,0 +1,137 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.druid.common.jackson;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.core.type.TypeReference;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializerProvider;
+import org.apache.druid.java.util.common.jackson.JacksonUtils;
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Objects;
+
+public class JacksonUtilsTest
+{
+  @Test
+  public void testWriteObjectUsingSerializerProvider() throws IOException
+  {
+    final ByteArrayOutputStream baos = new ByteArrayOutputStream();
+
+    final ObjectMapper objectMapper = new ObjectMapper();
+    final SerializerProvider serializers = objectMapper.getSerializerProviderInstance();
+
+    final JsonGenerator jg = objectMapper.getFactory().createGenerator(baos);
+    jg.writeStartArray();
+    JacksonUtils.writeObjectUsingSerializerProvider(jg, serializers, new SerializableClass(2));
+    JacksonUtils.writeObjectUsingSerializerProvider(jg, serializers, null);
+    JacksonUtils.writeObjectUsingSerializerProvider(jg, serializers, new SerializableClass(3));
+    jg.writeEndArray();
+    jg.close();
+
+    final List<SerializableClass> deserializedValues = objectMapper.readValue(
+        baos.toByteArray(),
+        new TypeReference<List<SerializableClass>>() {}
+    );
+
+    Assert.assertEquals(
+        Arrays.asList(new SerializableClass(2), null, new SerializableClass(3)),
+        deserializedValues
+    );
+  }
+
+  @Test
+  public void testWritePrimitivesUsingSerializerProvider() throws IOException
+  {
+    final ByteArrayOutputStream baos = new ByteArrayOutputStream();
+
+    final ObjectMapper objectMapper = new ObjectMapper();
+    final SerializerProvider serializers = objectMapper.getSerializerProviderInstance();
+
+    final JsonGenerator jg = objectMapper.getFactory().createGenerator(baos);
+    jg.writeStartArray();
+    JacksonUtils.writeObjectUsingSerializerProvider(jg, serializers, "foo");
+    JacksonUtils.writeObjectUsingSerializerProvider(jg, serializers, null);
+    JacksonUtils.writeObjectUsingSerializerProvider(jg, serializers, 1.23);
+    jg.writeEndArray();
+    jg.close();
+
+    final List<Object> deserializedValues = objectMapper.readValue(
+        baos.toByteArray(),
+        new TypeReference<List<Object>>() {}
+    );
+
+    Assert.assertEquals(
+        Arrays.asList("foo", null, 1.23),
+        deserializedValues
+    );
+  }
+
+  public static class SerializableClass
+  {
+    private final int value;
+
+    @JsonCreator
+    public SerializableClass(@JsonProperty("value") final int value)
+    {
+      this.value = value;
+    }
+
+    @JsonProperty
+    public int getValue()
+    {
+      return value;
+    }
+
+    @Override
+    public boolean equals(Object o)
+    {
+      if (this == o) {
+        return true;
+      }
+      if (o == null || getClass() != o.getClass()) {
+        return false;
+      }
+      SerializableClass that = (SerializableClass) o;
+      return value == that.value;
+    }
+
+    @Override
+    public int hashCode()
+    {
+      return Objects.hash(value);
+    }
+
+    @Override
+    public String toString()
+    {
+      return "SerializableClass{" +
+             "value=" + value +
+             '}';
+    }
+  }
+}

core/src/test/java/org/apache/druid/data/input/impl/prefetch/JsonIteratorTest.java

@@ -23,9 +23,11 @@ package org.apache.druid.data.input.impl.prefetch;
 import com.fasterxml.jackson.core.JsonGenerator;
 import com.fasterxml.jackson.core.type.TypeReference;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializerProvider;
 import com.fasterxml.jackson.dataformat.smile.SmileFactory;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
+import org.apache.druid.java.util.common.jackson.JacksonUtils;
 import org.junit.Assert;
 import org.junit.Test;
 
@@ -50,9 +52,10 @@ public class JsonIteratorTest
     };
     try (FileOutputStream fos = new FileOutputStream(testFile)) {
       final JsonGenerator jg = mapper.getFactory().createGenerator(fos);
+      final SerializerProvider serializers = mapper.getSerializerProviderInstance();
       jg.writeStartArray();
       for (Map<String, Object> mapFromList : expectedList) {
-        jg.writeObject(mapFromList);
+        JacksonUtils.writeObjectUsingSerializerProvider(jg, serializers, mapFromList);
       }
       jg.writeEndArray();
       jg.close();

docs/querying/groupbyquery.md

@@ -409,6 +409,7 @@ Supported runtime properties:
 |--------|-----------|-------|
 |`druid.query.groupBy.defaultStrategy`|Default groupBy query strategy.|v2|
 |`druid.query.groupBy.singleThreaded`|Merge results using a single thread.|false|
+|`druid.query.groupBy.intermediateResultAsMapCompat`|Whether Brokers are able to understand map-based result rows. Setting this to `true` adds some overhead to all groupBy queries. It is required for compatibility with data servers running versions older than 0.16.0, which introduced [array-based result rows](#array-based-result-rows).|false|
 
 Supported query contexts:
 

processing/src/main/java/org/apache/druid/jackson/DruidDefaultSerializersModule.java

@@ -31,6 +31,7 @@ import org.apache.druid.java.util.common.DateTimes;
 import org.apache.druid.java.util.common.guava.Accumulator;
 import org.apache.druid.java.util.common.guava.Sequence;
 import org.apache.druid.java.util.common.guava.Yielder;
+import org.apache.druid.java.util.common.jackson.JacksonUtils;
 import org.apache.druid.query.context.ResponseContext;
 import org.apache.druid.query.context.ResponseContextDeserializer;
 import org.joda.time.DateTimeZone;
@@ -93,11 +94,26 @@ public class DruidDefaultSerializersModule extends SimpleModule
                 null,
                 new Accumulator<Object, Object>()
                 {
+                  // Save allocations in jgen.writeObject by caching serializer.
+                  JsonSerializer<Object> serializer = null;
+                  Class<?> serializerClass = null;
+
                   @Override
-                  public Object accumulate(Object o, Object o1)
+                  public Object accumulate(Object ignored, Object object)
                   {
                     try {
-                      jgen.writeObject(o1);
+                      if (object == null) {
+                        jgen.writeNull();
+                      } else {
+                        final Class<?> clazz = object.getClass();
+
+                        if (serializerClass != clazz) {
+                          serializer = JacksonUtils.getSerializer(provider, clazz);
+                          serializerClass = clazz;
+                        }
+
+                        serializer.serialize(object, jgen, provider);
+                      }
                     }
                     catch (IOException e) {
                       throw new RuntimeException(e);
@@ -119,11 +135,27 @@ public class DruidDefaultSerializersModule extends SimpleModule
           public void serialize(Yielder yielder, final JsonGenerator jgen, SerializerProvider provider)
               throws IOException
           {
+            // Save allocations in jgen.writeObject by caching serializer.
+            JsonSerializer<Object> serializer = null;
+            Class<?> serializerClass = null;
+
             try {
               jgen.writeStartArray();
               while (!yielder.isDone()) {
                 final Object o = yielder.get();
-                jgen.writeObject(o);
+                if (o == null) {
+                  jgen.writeNull();
+                } else {
+                  final Class<?> clazz = o.getClass();
+
+                  if (serializerClass != clazz) {
+                    serializer = JacksonUtils.getSerializer(provider, clazz);
+                    serializerClass = clazz;
+                  }
+
+                  serializer.serialize(o, jgen, provider);
+                }
+
                 yielder = yielder.next(null);
               }
               jgen.writeEndArray();

processing/src/main/java/org/apache/druid/query/groupby/GroupByQueryConfig.java

@@ -105,6 +105,9 @@ public class GroupByQueryConfig
   @JsonProperty
   private boolean vectorize = true;
 
+  @JsonProperty
+  private boolean intermediateResultAsMapCompat = false;
+
   @JsonProperty
   private boolean enableMultiValueUnnesting = true;
 
@@ -203,6 +206,11 @@ public class GroupByQueryConfig
     return vectorize;
   }
 
+  public boolean isIntermediateResultAsMapCompat()
+  {
+    return intermediateResultAsMapCompat;
+  }
+
   public boolean isForcePushDownNestedQuery()
   {
     return forcePushDownNestedQuery;

processing/src/main/java/org/apache/druid/query/groupby/GroupByQueryQueryToolChest.java

@@ -31,6 +31,7 @@ import com.fasterxml.jackson.databind.module.SimpleModule;
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Function;
 import com.google.common.base.Functions;
+import com.google.common.base.Supplier;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Lists;
 import com.google.inject.Inject;
@@ -40,6 +41,7 @@ import org.apache.druid.java.util.common.granularity.Granularity;
 import org.apache.druid.java.util.common.guava.MappedSequence;
 import org.apache.druid.java.util.common.guava.Sequence;
 import org.apache.druid.java.util.common.guava.Sequences;
+import org.apache.druid.java.util.common.jackson.JacksonUtils;
 import org.apache.druid.query.CacheStrategy;
 import org.apache.druid.query.DataSource;
 import org.apache.druid.query.Query;
@@ -91,21 +93,24 @@ public class GroupByQueryQueryToolChest extends QueryToolChest<ResultRow, GroupB
   public static final String GROUP_BY_MERGE_KEY = "groupByMerge";
 
   private final GroupByStrategySelector strategySelector;
+  private final GroupByQueryConfig queryConfig;
   private final GroupByQueryMetricsFactory queryMetricsFactory;
 
   @VisibleForTesting
   public GroupByQueryQueryToolChest(GroupByStrategySelector strategySelector)
   {
-    this(strategySelector, DefaultGroupByQueryMetricsFactory.instance());
+    this(strategySelector, GroupByQueryConfig::new, DefaultGroupByQueryMetricsFactory.instance());
   }
 
   @Inject
   public GroupByQueryQueryToolChest(
       GroupByStrategySelector strategySelector,
+      Supplier<GroupByQueryConfig> queryConfigSupplier,
       GroupByQueryMetricsFactory queryMetricsFactory
   )
   {
     this.strategySelector = strategySelector;
+    this.queryConfig = queryConfigSupplier.get();
     this.queryMetricsFactory = queryMetricsFactory;
   }
 
@@ -415,6 +420,12 @@ public class GroupByQueryQueryToolChest extends QueryToolChest<ResultRow, GroupB
   {
     final boolean resultAsArray = query.getContextBoolean(GroupByQueryConfig.CTX_KEY_ARRAY_RESULT_ROWS, false);
 
+    if (resultAsArray && !queryConfig.isIntermediateResultAsMapCompat()) {
+      // We can assume ResultRow are serialized and deserialized as arrays. No need for special decoration,
+      // and we can save the overhead of making a copy of the ObjectMapper.
+      return objectMapper;
+    }
+
     // Serializer that writes array- or map-based rows as appropriate, based on the "resultAsArray" setting.
     final JsonSerializer<ResultRow> serializer = new JsonSerializer<ResultRow>()
     {
@@ -426,9 +437,9 @@ public class GroupByQueryQueryToolChest extends QueryToolChest<ResultRow, GroupB
       ) throws IOException
       {
         if (resultAsArray) {
-          jg.writeObject(resultRow.getArray());
+          JacksonUtils.writeObjectUsingSerializerProvider(jg, serializers, resultRow.getArray());
         } else {
-          jg.writeObject(resultRow.toMapBasedRow(query));
+          JacksonUtils.writeObjectUsingSerializerProvider(jg, serializers, resultRow.toMapBasedRow(query));
         }
       }
     };

processing/src/main/java/org/apache/druid/query/groupby/epinephelinae/SpillingGrouper.java

@@ -22,6 +22,7 @@ package org.apache.druid.query.groupby.epinephelinae;
 import com.fasterxml.jackson.core.JsonGenerator;
 import com.fasterxml.jackson.databind.MappingIterator;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializerProvider;
 import com.google.common.base.Function;
 import com.google.common.base.Preconditions;
 import com.google.common.base.Supplier;
@@ -30,6 +31,7 @@ import net.jpountz.lz4.LZ4BlockInputStream;
 import net.jpountz.lz4.LZ4BlockOutputStream;
 import org.apache.druid.java.util.common.CloseableIterators;
 import org.apache.druid.java.util.common.io.Closer;
+import org.apache.druid.java.util.common.jackson.JacksonUtils;
 import org.apache.druid.java.util.common.logger.Logger;
 import org.apache.druid.java.util.common.parsers.CloseableIterator;
 import org.apache.druid.query.BaseQuery;
@@ -309,10 +311,11 @@ public class SpillingGrouper<KeyType> implements Grouper<KeyType>
         final LZ4BlockOutputStream compressedOut = new LZ4BlockOutputStream(out);
         final JsonGenerator jsonGenerator = spillMapper.getFactory().createGenerator(compressedOut)
     ) {
+      final SerializerProvider serializers = spillMapper.getSerializerProviderInstance();
+
       while (iterator.hasNext()) {
         BaseQuery.checkInterrupted();
-
+        JacksonUtils.writeObjectUsingSerializerProvider(jsonGenerator, serializers, iterator.next());
-        jsonGenerator.writeObject(iterator.next());
       }
 
       return out.getFile();

processing/src/test/java/org/apache/druid/jackson/DefaultObjectMapperTest.java

@@ -22,11 +22,18 @@ package org.apache.druid.jackson;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import org.apache.druid.java.util.common.DateTimes;
 import org.apache.druid.java.util.common.StringUtils;
+import org.apache.druid.java.util.common.guava.Sequence;
+import org.apache.druid.java.util.common.guava.Sequences;
+import org.apache.druid.java.util.common.guava.Yielders;
 import org.joda.time.DateTime;
+import org.joda.time.DateTimeZone;
 import org.junit.Assert;
 import org.junit.Test;
 
+import java.util.Arrays;
+
 /**
+ *
  */
 public class DefaultObjectMapperTest
 {
@@ -39,4 +46,25 @@ public class DefaultObjectMapperTest
 
     Assert.assertEquals(StringUtils.format("\"%s\"", time), mapper.writeValueAsString(time));
   }
+
+  @Test
+  public void testYielder() throws Exception
+  {
+    final Sequence<Object> sequence = Sequences.simple(
+        Arrays.asList(
+            "a",
+            "b",
+            null,
+            DateTimes.utc(2L),
+            5,
+            DateTimeZone.UTC,
+            "c"
+        )
+    );
+
+    Assert.assertEquals(
+        "[\"a\",\"b\",null,\"1970-01-01T00:00:00.002Z\",5,\"UTC\",\"c\"]",
+        mapper.writeValueAsString(Yielders.each(sequence))
+    );
+  }
 }

processing/src/test/java/org/apache/druid/query/groupby/GroupByQueryQueryToolChestTest.java

@@ -538,7 +538,7 @@ public class GroupByQueryQueryToolChestTest extends InitializedNullHandlingTest
         .build();
 
     CacheStrategy<ResultRow, Object, GroupByQuery> strategy =
-        new GroupByQueryQueryToolChest(null, null).getCacheStrategy(
+        new GroupByQueryQueryToolChest(null).getCacheStrategy(
             query1
         );
 
@@ -592,6 +592,100 @@ public class GroupByQueryQueryToolChestTest extends InitializedNullHandlingTest
     final Object[] rowObjects = {DateTimes.of("2000").getMillis(), "foo", 100, 10.0};
     final ResultRow resultRow = ResultRow.of(rowObjects);
 
+    Assert.assertArrayEquals(
+        "standard mapper reads ResultRows",
+        rowObjects,
+        objectMapper.readValue(
+            arraysObjectMapper.writeValueAsBytes(resultRow),
+            Object[].class
+        )
+    );
+
+    Assert.assertEquals(
+        "standard mapper reads MapBasedRows",
+        resultRow.toMapBasedRow(query),
+        objectMapper.readValue(
+            mapsObjectMapper.writeValueAsBytes(resultRow),
+            Row.class
+        )
+    );
+
+    Assert.assertEquals(
+        "array mapper reads arrays",
+        resultRow,
+        arraysObjectMapper.readValue(
+            arraysObjectMapper.writeValueAsBytes(resultRow),
+            ResultRow.class
+        )
+    );
+
+    Assert.assertEquals(
+        "array mapper reads arrays (2)",
+        resultRow,
+        arraysObjectMapper.readValue(
+            StringUtils.format("[%s, \"foo\", 100, 10.0]", DateTimes.of("2000").getMillis()),
+            ResultRow.class
+        )
+    );
+
+    Assert.assertEquals(
+        "map mapper reads arrays",
+        resultRow,
+        mapsObjectMapper.readValue(
+            arraysObjectMapper.writeValueAsBytes(resultRow),
+            ResultRow.class
+        )
+    );
+
+    Assert.assertEquals(
+        "map mapper reads maps",
+        resultRow,
+        mapsObjectMapper.readValue(
+            mapsObjectMapper.writeValueAsBytes(resultRow),
+            ResultRow.class
+        )
+    );
+  }
+
+  @Test
+  public void testResultSerdeIntermediateResultAsMapCompat() throws Exception
+  {
+    final GroupByQuery query = GroupByQuery
+        .builder()
+        .setDataSource(QueryRunnerTestHelper.DATA_SOURCE)
+        .setQuerySegmentSpec(QueryRunnerTestHelper.FIRST_TO_THIRD)
+        .setDimensions(Collections.singletonList(DefaultDimensionSpec.of("test")))
+        .setAggregatorSpecs(Collections.singletonList(QueryRunnerTestHelper.ROWS_COUNT))
+        .setPostAggregatorSpecs(Collections.singletonList(new ConstantPostAggregator("post", 10)))
+        .setGranularity(QueryRunnerTestHelper.DAY_GRAN)
+        .build();
+
+    final GroupByQueryQueryToolChest toolChest = new GroupByQueryQueryToolChest(
+        null,
+        () -> new GroupByQueryConfig()
+        {
+          @Override
+          public boolean isIntermediateResultAsMapCompat()
+          {
+            return true;
+          }
+        },
+        null
+    );
+
+    final ObjectMapper objectMapper = TestHelper.makeJsonMapper();
+    final ObjectMapper arraysObjectMapper = toolChest.decorateObjectMapper(
+        objectMapper,
+        query.withOverriddenContext(ImmutableMap.of(GroupByQueryConfig.CTX_KEY_ARRAY_RESULT_ROWS, true))
+    );
+    final ObjectMapper mapsObjectMapper = toolChest.decorateObjectMapper(
+        objectMapper,
+        query.withOverriddenContext(ImmutableMap.of(GroupByQueryConfig.CTX_KEY_ARRAY_RESULT_ROWS, false))
+    );
+
+    final Object[] rowObjects = {DateTimes.of("2000").getMillis(), "foo", 100, 10.0};
+    final ResultRow resultRow = ResultRow.of(rowObjects);
+
 
     Assert.assertEquals(
         resultRow,
@@ -601,9 +695,46 @@ public class GroupByQueryQueryToolChestTest extends InitializedNullHandlingTest
         )
     );
 
-    TestHelper.assertRow("",
+    Assert.assertArrayEquals(
+        "standard mapper reads ResultRows",
+        rowObjects,
+        objectMapper.readValue(
+            arraysObjectMapper.writeValueAsBytes(resultRow),
+            Object[].class
+        )
+    );
+
+    Assert.assertEquals(
+        "standard mapper reads MapBasedRows",
+        resultRow.toMapBasedRow(query),
+        objectMapper.readValue(
+            mapsObjectMapper.writeValueAsBytes(resultRow),
+            Row.class
+        )
+    );
+
+    Assert.assertEquals(
+        "array mapper reads arrays",
         resultRow,
-                         arraysObjectMapper.readValue(
+        arraysObjectMapper.readValue(
+            arraysObjectMapper.writeValueAsBytes(resultRow),
+            ResultRow.class
+        )
+    );
+
+    Assert.assertEquals(
+        "array mapper reads maps",
+        resultRow,
+        arraysObjectMapper.readValue(
+            mapsObjectMapper.writeValueAsBytes(resultRow),
+            ResultRow.class
+        )
+    );
+
+    TestHelper.assertRow(
+        "array mapper reads maps (2)",
+        resultRow,
+        arraysObjectMapper.readValue(
             StringUtils.format(
                 "{\"version\":\"v1\","
                 + "\"timestamp\":\"%s\","
@@ -616,42 +747,8 @@ public class GroupByQueryQueryToolChestTest extends InitializedNullHandlingTest
         )
     );
 
-    Assert.assertArrayEquals(
-        rowObjects,
-        objectMapper.readValue(
-            arraysObjectMapper.writeValueAsBytes(resultRow),
-            Object[].class
-        )
-    );
-
     Assert.assertEquals(
-        resultRow.toMapBasedRow(query),
+        "map mapper reads arrays",
-        objectMapper.readValue(
-            mapsObjectMapper.writeValueAsBytes(resultRow),
-            Row.class
-        )
-    );
-
-    Assert.assertEquals(
-        "arrays read arrays",
-        resultRow,
-        arraysObjectMapper.readValue(
-            arraysObjectMapper.writeValueAsBytes(resultRow),
-            ResultRow.class
-        )
-    );
-
-    Assert.assertEquals(
-        "arrays read maps",
-        resultRow,
-        arraysObjectMapper.readValue(
-            mapsObjectMapper.writeValueAsBytes(resultRow),
-            ResultRow.class
-        )
-    );
-
-    Assert.assertEquals(
-        "maps read arrays",
         resultRow,
         mapsObjectMapper.readValue(
             arraysObjectMapper.writeValueAsBytes(resultRow),
@@ -660,7 +757,7 @@ public class GroupByQueryQueryToolChestTest extends InitializedNullHandlingTest
     );
 
     Assert.assertEquals(
-        "maps read maps",
+        "map mapper reads maps",
         resultRow,
         mapsObjectMapper.readValue(
             mapsObjectMapper.writeValueAsBytes(resultRow),
@@ -689,7 +786,7 @@ public class GroupByQueryQueryToolChestTest extends InitializedNullHandlingTest
                     .add("uniques", null)
                     .add("const", ColumnType.LONG)
                     .build(),
-        new GroupByQueryQueryToolChest(null, null).resultArraySignature(query)
+        new GroupByQueryQueryToolChest(null).resultArraySignature(query)
     );
   }
 
@@ -714,7 +811,7 @@ public class GroupByQueryQueryToolChestTest extends InitializedNullHandlingTest
                     .add("uniques", null)
                     .add("const", ColumnType.LONG)
                     .build(),
-        new GroupByQueryQueryToolChest(null, null).resultArraySignature(query)
+        new GroupByQueryQueryToolChest(null).resultArraySignature(query)
     );
   }
 
@@ -735,7 +832,7 @@ public class GroupByQueryQueryToolChestTest extends InitializedNullHandlingTest
             new Object[]{"foo", 1L, 2L, 3L, 1L},
             new Object[]{"bar", 4L, 5L, 6L, 1L}
         ),
-        new GroupByQueryQueryToolChest(null, null).resultsAsArrays(
+        new GroupByQueryQueryToolChest(null).resultsAsArrays(
             query,
             Sequences.simple(
                 ImmutableList.of(
@@ -764,7 +861,7 @@ public class GroupByQueryQueryToolChestTest extends InitializedNullHandlingTest
             new Object[]{DateTimes.of("2000-01-01").getMillis(), "foo", 1L, 2L, 3L, 1L},
             new Object[]{DateTimes.of("2000-01-02").getMillis(), "bar", 4L, 5L, 6L, 1L}
         ),
-        new GroupByQueryQueryToolChest(null, null).resultsAsArrays(
+        new GroupByQueryQueryToolChest(null).resultsAsArrays(
             query,
             Sequences.simple(
                 ImmutableList.of(
@@ -780,7 +877,7 @@ public class GroupByQueryQueryToolChestTest extends InitializedNullHandlingTest
   public void testCanPerformSubqueryOnGroupBys()
   {
     Assert.assertTrue(
-        new GroupByQueryQueryToolChest(null, null).canPerformSubquery(
+        new GroupByQueryQueryToolChest(null).canPerformSubquery(
             new GroupByQuery.Builder()
                 .setDataSource(
                     new QueryDataSource(
@@ -802,7 +899,7 @@ public class GroupByQueryQueryToolChestTest extends InitializedNullHandlingTest
   public void testCanPerformSubqueryOnTimeseries()
   {
     Assert.assertFalse(
-        new GroupByQueryQueryToolChest(null, null).canPerformSubquery(
+        new GroupByQueryQueryToolChest(null).canPerformSubquery(
             Druids.newTimeseriesQueryBuilder()
                   .dataSource(QueryRunnerTestHelper.DATA_SOURCE)
                   .intervals(QueryRunnerTestHelper.FULL_ON_INTERVAL_SPEC)
@@ -816,7 +913,7 @@ public class GroupByQueryQueryToolChestTest extends InitializedNullHandlingTest
   public void testCanPerformSubqueryOnGroupByOfTimeseries()
   {
     Assert.assertFalse(
-        new GroupByQueryQueryToolChest(null, null).canPerformSubquery(
+        new GroupByQueryQueryToolChest(null).canPerformSubquery(
             new GroupByQuery.Builder()
                 .setDataSource(
                     new QueryDataSource(
@@ -886,12 +983,17 @@ public class GroupByQueryQueryToolChestTest extends InitializedNullHandlingTest
         .build();
 
     CacheStrategy<ResultRow, Object, GroupByQuery> strategy =
-        new GroupByQueryQueryToolChest(null, null).getCacheStrategy(
+        new GroupByQueryQueryToolChest(null).getCacheStrategy(
             query1
         );
 
     // test timestamps that result in integer size millis
-    final ResultRow result1 = ResultRow.of(123L, dimValue, 1, getIntermediateComplexValue(valueType.getType(), dimValue));
+    final ResultRow result1 = ResultRow.of(
+        123L,
+        dimValue,
+        1,
+        getIntermediateComplexValue(valueType.getType(), dimValue)
+    );
 
     Object preparedValue = strategy.prepareForSegmentLevelCache().apply(result1);
 

server/src/main/java/org/apache/druid/client/cache/BackgroundCachePopulator.java

@@ -21,6 +21,7 @@ package org.apache.druid.client.cache;
 
 import com.fasterxml.jackson.core.JsonGenerator;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializerProvider;
 import com.google.common.base.Preconditions;
 import com.google.common.util.concurrent.FutureCallback;
 import com.google.common.util.concurrent.Futures;
@@ -31,6 +32,7 @@ import org.apache.druid.common.guava.GuavaUtils;
 import org.apache.druid.java.util.common.concurrent.Execs;
 import org.apache.druid.java.util.common.guava.Sequence;
 import org.apache.druid.java.util.common.guava.Sequences;
+import org.apache.druid.java.util.common.jackson.JacksonUtils;
 import org.apache.druid.java.util.common.logger.Logger;
 
 import java.io.ByteArrayOutputStream;
@@ -120,10 +122,11 @@ public class BackgroundCachePopulator implements CachePopulator
   {
     try {
       final ByteArrayOutputStream bytes = new ByteArrayOutputStream();
+      final SerializerProvider serializers = objectMapper.getSerializerProviderInstance();
 
       try (JsonGenerator gen = objectMapper.getFactory().createGenerator(bytes)) {
         for (CacheType result : results) {
-          gen.writeObject(result);
+          JacksonUtils.writeObjectUsingSerializerProvider(gen, serializers, result);
 
           if (maxEntrySize > 0 && bytes.size() > maxEntrySize) {
             cachePopulatorStats.incrementOversized();

server/src/main/java/org/apache/druid/client/cache/ForegroundCachePopulator.java

@@ -21,11 +21,13 @@ package org.apache.druid.client.cache;
 
 import com.fasterxml.jackson.core.JsonGenerator;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializerProvider;
 import com.google.common.base.Preconditions;
 import org.apache.commons.lang.mutable.MutableBoolean;
 import org.apache.druid.java.util.common.guava.Sequence;
 import org.apache.druid.java.util.common.guava.SequenceWrapper;
 import org.apache.druid.java.util.common.guava.Sequences;
+import org.apache.druid.java.util.common.jackson.JacksonUtils;
 import org.apache.druid.java.util.common.logger.Logger;
 
 import java.io.ByteArrayOutputStream;
@@ -65,6 +67,7 @@ public class ForegroundCachePopulator implements CachePopulator
   {
     final ByteArrayOutputStream bytes = new ByteArrayOutputStream();
     final MutableBoolean tooBig = new MutableBoolean(false);
+    final SerializerProvider serializers = objectMapper.getSerializerProviderInstance();
     final JsonGenerator jsonGenerator;
 
     try {
@@ -80,7 +83,7 @@ public class ForegroundCachePopulator implements CachePopulator
             input -> {
               if (!tooBig.isTrue()) {
                 try {
-                  jsonGenerator.writeObject(cacheFn.apply(input));
+                  JacksonUtils.writeObjectUsingSerializerProvider(jsonGenerator, serializers, cacheFn.apply(input));
 
                   // Not flushing jsonGenerator before checking this, but should be ok since Jackson buffers are
                   // typically just a few KB, and we don't want to waste cycles flushing.

server/src/main/java/org/apache/druid/metadata/input/SqlEntity.java

@@ -21,9 +21,11 @@ package org.apache.druid.metadata.input;
 
 import com.fasterxml.jackson.core.JsonGenerator;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializerProvider;
 import com.google.common.base.Preconditions;
 import org.apache.druid.data.input.InputEntity;
 import org.apache.druid.java.util.common.StringUtils;
+import org.apache.druid.java.util.common.jackson.JacksonUtils;
 import org.apache.druid.java.util.common.logger.Logger;
 import org.apache.druid.metadata.SQLFirehoseDatabaseConnector;
 import org.apache.druid.metadata.SQLMetadataStorageActionHandler;
@@ -117,7 +119,8 @@ public class SqlEntity implements InputEntity
       throws IOException
   {
     try (FileOutputStream fos = new FileOutputStream(tempFile);
-         final JsonGenerator jg = objectMapper.getFactory().createGenerator(fos);) {
+         final JsonGenerator jg = objectMapper.getFactory().createGenerator(fos)) {
+      final SerializerProvider serializers = objectMapper.getSerializerProviderInstance();
 
       // Execute the sql query and lazily retrieve the results into the file in json format.
       // foldCase is useful to handle differences in case sensitivity behavior across databases.
@@ -152,7 +155,7 @@ public class SqlEntity implements InputEntity
             ).iterator();
             jg.writeStartArray();
             while (resultIterator.hasNext()) {
-              jg.writeObject(resultIterator.next());
+              JacksonUtils.writeObjectUsingSerializerProvider(jg, serializers, resultIterator.next());
             }
             jg.writeEndArray();
             jg.close();

server/src/main/java/org/apache/druid/query/ResultLevelCachingQueryRunner.java

@@ -22,6 +22,7 @@ package org.apache.druid.query;
 import com.fasterxml.jackson.core.JsonGenerator;
 import com.fasterxml.jackson.core.type.TypeReference;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializerProvider;
 import com.google.common.base.Function;
 import com.google.common.base.Preconditions;
 import com.google.common.collect.ImmutableMap;
@@ -33,6 +34,7 @@ import org.apache.druid.java.util.common.StringUtils;
 import org.apache.druid.java.util.common.guava.Sequence;
 import org.apache.druid.java.util.common.guava.SequenceWrapper;
 import org.apache.druid.java.util.common.guava.Sequences;
+import org.apache.druid.java.util.common.jackson.JacksonUtils;
 import org.apache.druid.java.util.common.logger.Logger;
 import org.apache.druid.query.context.ResponseContext;
 import org.apache.druid.server.QueryResource;
@@ -247,6 +249,7 @@ public class ResultLevelCachingQueryRunner<T> implements QueryRunner<T>
   {
     private final Cache cache;
     private final ObjectMapper mapper;
+    private final SerializerProvider serialiers;
     private final Cache.NamedKey key;
     private final CacheConfig cacheConfig;
     @Nullable
@@ -262,6 +265,7 @@ public class ResultLevelCachingQueryRunner<T> implements QueryRunner<T>
     {
       this.cache = cache;
       this.mapper = mapper;
+      this.serialiers = mapper.getSerializerProviderInstance();
       this.key = key;
       this.cacheConfig = cacheConfig;
       this.cacheObjectStream = shouldPopulate ? new ByteArrayOutputStream() : null;
@@ -285,7 +289,7 @@ public class ResultLevelCachingQueryRunner<T> implements QueryRunner<T>
       Preconditions.checkNotNull(cacheObjectStream, "cacheObjectStream");
       int cacheLimit = cacheConfig.getResultLevelCacheLimit();
       try (JsonGenerator gen = mapper.getFactory().createGenerator(cacheObjectStream)) {
-        gen.writeObject(cacheFn.apply(resultEntry));
+        JacksonUtils.writeObjectUsingSerializerProvider(gen, serialiers, cacheFn.apply(resultEntry));
         if (cacheLimit > 0 && cacheObjectStream.size() > cacheLimit) {
           stopPopulating();
         }

server/src/test/java/org/apache/druid/client/CachingQueryRunnerTest.java

@@ -21,6 +21,7 @@ package org.apache.druid.client;
 
 import com.fasterxml.jackson.core.JsonGenerator;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializerProvider;
 import com.google.common.base.Function;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Iterables;
@@ -45,6 +46,7 @@ import org.apache.druid.java.util.common.granularity.Granularities;
 import org.apache.druid.java.util.common.guava.Sequence;
 import org.apache.druid.java.util.common.guava.SequenceWrapper;
 import org.apache.druid.java.util.common.guava.Sequences;
+import org.apache.druid.java.util.common.jackson.JacksonUtils;
 import org.apache.druid.java.util.emitter.service.ServiceEmitter;
 import org.apache.druid.query.CacheStrategy;
 import org.apache.druid.query.Druids;
@@ -495,8 +497,9 @@ public class CachingQueryRunnerTest
     final ByteArrayOutputStream bytes = new ByteArrayOutputStream();
 
     try (JsonGenerator gen = objectMapper.getFactory().createGenerator(bytes)) {
+      final SerializerProvider serializers = objectMapper.getSerializerProviderInstance();
       for (T result : results) {
-        gen.writeObject(result);
+        JacksonUtils.writeObjectUsingSerializerProvider(gen, serializers, result);
       }
     }
 

server/src/test/java/org/apache/druid/segment/realtime/firehose/SqlFirehoseTest.java

@@ -22,6 +22,7 @@ package org.apache.druid.segment.realtime.firehose;
 import com.fasterxml.jackson.core.JsonGenerator;
 import com.fasterxml.jackson.core.type.TypeReference;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializerProvider;
 import com.fasterxml.jackson.dataformat.smile.SmileFactory;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
@@ -34,6 +35,7 @@ import org.apache.druid.data.input.impl.TimeAndDimsParseSpec;
 import org.apache.druid.data.input.impl.TimestampSpec;
 import org.apache.druid.data.input.impl.prefetch.JsonIterator;
 import org.apache.druid.java.util.common.FileUtils;
+import org.apache.druid.java.util.common.jackson.JacksonUtils;
 import org.apache.druid.math.expr.ExprMacroTable;
 import org.apache.druid.segment.transform.ExpressionTransform;
 import org.apache.druid.segment.transform.TransformSpec;
@@ -84,8 +86,9 @@ public class SqlFirehoseTest
       File file = new File(TEST_DIR, "test_" + i++);
       try (FileOutputStream fos = new FileOutputStream(file)) {
         final JsonGenerator jg = objectMapper.getFactory().createGenerator(fos);
+        final SerializerProvider serializers = objectMapper.getSerializerProviderInstance();
         jg.writeStartArray();
-        jg.writeObject(m);
+        JacksonUtils.writeObjectUsingSerializerProvider(jg, serializers, m);
         jg.writeEndArray();
         jg.close();
         testFile.add(new FileInputStream(file));

sql/src/main/java/org/apache/druid/sql/http/ArrayLinesWriter.java

@@ -22,7 +22,9 @@ package org.apache.druid.sql.http;
 import com.fasterxml.jackson.core.JsonGenerator;
 import com.fasterxml.jackson.core.io.SerializedString;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializerProvider;
 import org.apache.calcite.rel.type.RelDataType;
+import org.apache.druid.java.util.common.jackson.JacksonUtils;
 
 import javax.annotation.Nullable;
 import java.io.IOException;
@@ -30,11 +32,13 @@ import java.io.OutputStream;
 
 public class ArrayLinesWriter implements ResultFormat.Writer
 {
-  private final OutputStream outputStream;
+  private final SerializerProvider serializers;
   private final JsonGenerator jsonGenerator;
+  private final OutputStream outputStream;
 
   public ArrayLinesWriter(final OutputStream outputStream, final ObjectMapper jsonMapper) throws IOException
   {
+    this.serializers = jsonMapper.getSerializerProviderInstance();
     this.outputStream = outputStream;
     this.jsonGenerator = jsonMapper.writer().getFactory().createGenerator(outputStream);
     jsonGenerator.setRootValueSeparator(new SerializedString("\n"));
@@ -75,7 +79,7 @@ public class ArrayLinesWriter implements ResultFormat.Writer
   @Override
   public void writeRowField(final String name, @Nullable final Object value) throws IOException
   {
-    jsonGenerator.writeObject(value);
+    JacksonUtils.writeObjectUsingSerializerProvider(jsonGenerator, serializers, value);
   }
 
   @Override

sql/src/main/java/org/apache/druid/sql/http/ArrayWriter.java

@@ -21,7 +21,9 @@ package org.apache.druid.sql.http;
 
 import com.fasterxml.jackson.core.JsonGenerator;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializerProvider;
 import org.apache.calcite.rel.type.RelDataType;
+import org.apache.druid.java.util.common.jackson.JacksonUtils;
 import org.apache.druid.segment.column.RowSignature;
 import org.apache.druid.segment.column.TypeSignature;
 import org.apache.druid.sql.calcite.table.RowSignatures;
@@ -32,11 +34,13 @@ import java.io.OutputStream;
 
 public class ArrayWriter implements ResultFormat.Writer
 {
+  private final SerializerProvider serializers;
   private final JsonGenerator jsonGenerator;
   private final OutputStream outputStream;
 
   public ArrayWriter(final OutputStream outputStream, final ObjectMapper jsonMapper) throws IOException
   {
+    this.serializers = jsonMapper.getSerializerProviderInstance();
     this.jsonGenerator = jsonMapper.getFactory().createGenerator(outputStream);
     this.outputStream = outputStream;
 
@@ -79,7 +83,7 @@ public class ArrayWriter implements ResultFormat.Writer
   @Override
   public void writeRowField(final String name, @Nullable final Object value) throws IOException
   {
-    jsonGenerator.writeObject(value);
+    JacksonUtils.writeObjectUsingSerializerProvider(jsonGenerator, serializers, value);
   }
 
   @Override

sql/src/main/java/org/apache/druid/sql/http/ObjectLinesWriter.java

@@ -22,7 +22,9 @@ package org.apache.druid.sql.http;
 import com.fasterxml.jackson.core.JsonGenerator;
 import com.fasterxml.jackson.core.io.SerializedString;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializerProvider;
 import org.apache.calcite.rel.type.RelDataType;
+import org.apache.druid.java.util.common.jackson.JacksonUtils;
 
 import javax.annotation.Nullable;
 import java.io.IOException;
@@ -30,11 +32,13 @@ import java.io.OutputStream;
 
 public class ObjectLinesWriter implements ResultFormat.Writer
 {
-  private final OutputStream outputStream;
+  private final SerializerProvider serializers;
   private final JsonGenerator jsonGenerator;
+  private final OutputStream outputStream;
 
   public ObjectLinesWriter(final OutputStream outputStream, final ObjectMapper jsonMapper) throws IOException
   {
+    this.serializers = jsonMapper.getSerializerProviderInstance();
     this.outputStream = outputStream;
     this.jsonGenerator = jsonMapper.writer().getFactory().createGenerator(outputStream);
     jsonGenerator.setRootValueSeparator(new SerializedString("\n"));
@@ -76,7 +80,7 @@ public class ObjectLinesWriter implements ResultFormat.Writer
   public void writeRowField(final String name, @Nullable final Object value) throws IOException
   {
     jsonGenerator.writeFieldName(name);
-    jsonGenerator.writeObject(value);
+    JacksonUtils.writeObjectUsingSerializerProvider(jsonGenerator, serializers, value);
   }
 
   @Override

sql/src/main/java/org/apache/druid/sql/http/ObjectWriter.java

@@ -21,7 +21,9 @@ package org.apache.druid.sql.http;
 
 import com.fasterxml.jackson.core.JsonGenerator;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializerProvider;
 import org.apache.calcite.rel.type.RelDataType;
+import org.apache.druid.java.util.common.jackson.JacksonUtils;
 import org.apache.druid.segment.column.RowSignature;
 import org.apache.druid.segment.column.TypeSignature;
 import org.apache.druid.sql.calcite.table.RowSignatures;
@@ -35,11 +37,13 @@ public class ObjectWriter implements ResultFormat.Writer
   static final String TYPE_HEADER_NAME = "type";
   static final String SQL_TYPE_HEADER_NAME = "sqlType";
 
+  private final SerializerProvider serializers;
   private final JsonGenerator jsonGenerator;
   private final OutputStream outputStream;
 
   public ObjectWriter(final OutputStream outputStream, final ObjectMapper jsonMapper) throws IOException
   {
+    this.serializers = jsonMapper.getSerializerProviderInstance();
     this.jsonGenerator = jsonMapper.getFactory().createGenerator(outputStream);
     this.outputStream = outputStream;
 
@@ -83,7 +87,7 @@ public class ObjectWriter implements ResultFormat.Writer
   public void writeRowField(final String name, @Nullable final Object value) throws IOException
   {
     jsonGenerator.writeFieldName(name);
-    jsonGenerator.writeObject(value);
+    JacksonUtils.writeObjectUsingSerializerProvider(jsonGenerator, serializers, value);
   }
 
   @Override