diff --git a/extensions-contrib/distinctcount/src/main/java/org/apache/druid/query/aggregation/distinctcount/DistinctCountAggregatorFactory.java b/extensions-contrib/distinctcount/src/main/java/org/apache/druid/query/aggregation/distinctcount/DistinctCountAggregatorFactory.java
index 524cc376693..08f5136bc82 100644
--- a/extensions-contrib/distinctcount/src/main/java/org/apache/druid/query/aggregation/distinctcount/DistinctCountAggregatorFactory.java
+++ b/extensions-contrib/distinctcount/src/main/java/org/apache/druid/query/aggregation/distinctcount/DistinctCountAggregatorFactory.java
@@ -35,6 +35,7 @@ import org.apache.druid.query.dimension.DefaultDimensionSpec;
 import org.apache.druid.segment.ColumnSelectorFactory;
 import org.apache.druid.segment.DimensionSelector;
 
+import javax.annotation.Nullable;
 import java.nio.ByteBuffer;
 import java.util.Collections;
 import java.util.Comparator;
@@ -147,8 +148,9 @@ public class DistinctCountAggregatorFactory extends AggregatorFactory
     return object;
   }
 
+  @Nullable
   @Override
-  public Object finalizeComputation(Object object)
+  public Object finalizeComputation(@Nullable Object object)
   {
     return object;
   }
diff --git a/extensions-contrib/momentsketch/src/main/java/org/apache/druid/query/aggregation/momentsketch/aggregator/MomentSketchAggregatorFactory.java b/extensions-contrib/momentsketch/src/main/java/org/apache/druid/query/aggregation/momentsketch/aggregator/MomentSketchAggregatorFactory.java
index 918ad3e04ed..1abe6a1a9ae 100644
--- a/extensions-contrib/momentsketch/src/main/java/org/apache/druid/query/aggregation/momentsketch/aggregator/MomentSketchAggregatorFactory.java
+++ b/extensions-contrib/momentsketch/src/main/java/org/apache/druid/query/aggregation/momentsketch/aggregator/MomentSketchAggregatorFactory.java
@@ -206,8 +206,9 @@ public class MomentSketchAggregatorFactory extends AggregatorFactory
     );
   }
 
+  @Nullable
   @Override
-  public Object finalizeComputation(Object object)
+  public Object finalizeComputation(@Nullable Object object)
   {
     return object;
   }
diff --git a/extensions-contrib/moving-average-query/src/main/java/org/apache/druid/query/movingaverage/AveragerFactoryWrapper.java b/extensions-contrib/moving-average-query/src/main/java/org/apache/druid/query/movingaverage/AveragerFactoryWrapper.java
index f6f1d90b4f6..9e4118c5669 100644
--- a/extensions-contrib/moving-average-query/src/main/java/org/apache/druid/query/movingaverage/AveragerFactoryWrapper.java
+++ b/extensions-contrib/moving-average-query/src/main/java/org/apache/druid/query/movingaverage/AveragerFactoryWrapper.java
@@ -25,6 +25,7 @@ import org.apache.druid.query.aggregation.BufferAggregator;
 import org.apache.druid.query.movingaverage.averagers.AveragerFactory;
 import org.apache.druid.segment.ColumnSelectorFactory;
 
+import javax.annotation.Nullable;
 import java.util.Comparator;
 import java.util.List;
 
@@ -125,8 +126,9 @@ public class AveragerFactoryWrapper<T, R> extends AggregatorFactory
    * Not implemented. Throws UnsupportedOperationException.
    */
   @SuppressWarnings("unchecked")
+  @Nullable
   @Override
-  public Object finalizeComputation(Object object)
+  public Object finalizeComputation(@Nullable Object object)
   {
     return af.finalizeComputation((T) object);
   }
diff --git a/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestBuildSketchAggregatorFactory.java b/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestBuildSketchAggregatorFactory.java
index b12f3b32acd..08f88b66ae5 100644
--- a/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestBuildSketchAggregatorFactory.java
+++ b/extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/TDigestBuildSketchAggregatorFactory.java
@@ -190,8 +190,9 @@ public class TDigestBuildSketchAggregatorFactory extends AggregatorFactory
     return TDigestSketchUtils.deserialize(serializedSketch);
   }
 
+  @Nullable
   @Override
-  public Object finalizeComputation(Object object)
+  public Object finalizeComputation(@Nullable Object object)
   {
     return object;
   }
diff --git a/extensions-contrib/time-min-max/src/main/java/org/apache/druid/query/aggregation/TimestampAggregatorFactory.java b/extensions-contrib/time-min-max/src/main/java/org/apache/druid/query/aggregation/TimestampAggregatorFactory.java
index bf9b69020d3..40f9095891a 100644
--- a/extensions-contrib/time-min-max/src/main/java/org/apache/druid/query/aggregation/TimestampAggregatorFactory.java
+++ b/extensions-contrib/time-min-max/src/main/java/org/apache/druid/query/aggregation/TimestampAggregatorFactory.java
@@ -27,6 +27,7 @@ import org.apache.druid.segment.ColumnSelectorFactory;
 import org.apache.druid.segment.ColumnValueSelector;
 import org.joda.time.DateTime;
 
+import javax.annotation.Nullable;
 import java.nio.ByteBuffer;
 import java.sql.Timestamp;
 import java.util.Collections;
@@ -157,10 +158,11 @@ public class TimestampAggregatorFactory extends AggregatorFactory
     return object;
   }
 
+  @Nullable
   @Override
-  public Object finalizeComputation(Object object)
+  public Object finalizeComputation(@Nullable Object object)
   {
-    return DateTimes.utc((long) object);
+    return object == null ? null : DateTimes.utc((long) object);
   }
 
   @Override
diff --git a/extensions-core/datasketches/src/main/java/org/apache/druid/query/aggregation/datasketches/hll/HllSketchAggregatorFactory.java b/extensions-core/datasketches/src/main/java/org/apache/druid/query/aggregation/datasketches/hll/HllSketchAggregatorFactory.java
index b10c8c3b448..dbbeb5b7ae2 100644
--- a/extensions-core/datasketches/src/main/java/org/apache/druid/query/aggregation/datasketches/hll/HllSketchAggregatorFactory.java
+++ b/extensions-core/datasketches/src/main/java/org/apache/druid/query/aggregation/datasketches/hll/HllSketchAggregatorFactory.java
@@ -157,9 +157,13 @@ public abstract class HllSketchAggregatorFactory extends AggregatorFactory
     };
   }
 
+  @Nullable
   @Override
-  public Double finalizeComputation(final Object object)
+  public Double finalizeComputation(@Nullable final Object object)
   {
+    if (object == null) {
+      return null;
+    }
     final HllSketch sketch = (HllSketch) object;
     return sketch.getEstimate();
   }
diff --git a/extensions-core/datasketches/src/main/java/org/apache/druid/query/aggregation/datasketches/quantiles/DoublesSketchAggregatorFactory.java b/extensions-core/datasketches/src/main/java/org/apache/druid/query/aggregation/datasketches/quantiles/DoublesSketchAggregatorFactory.java
index 6b17ec7733e..f3b817dab89 100644
--- a/extensions-core/datasketches/src/main/java/org/apache/druid/query/aggregation/datasketches/quantiles/DoublesSketchAggregatorFactory.java
+++ b/extensions-core/datasketches/src/main/java/org/apache/druid/query/aggregation/datasketches/quantiles/DoublesSketchAggregatorFactory.java
@@ -240,10 +240,11 @@ public class DoublesSketchAggregatorFactory extends AggregatorFactory
     }
   }
 
+  @Nullable
   @Override
-  public Object finalizeComputation(final Object object)
+  public Object finalizeComputation(@Nullable final Object object)
   {
-    return ((DoublesSketch) object).getN();
+    return object == null ? null : ((DoublesSketch) object).getN();
   }
 
   @Override
diff --git a/extensions-core/datasketches/src/main/java/org/apache/druid/query/aggregation/datasketches/theta/SketchMergeAggregatorFactory.java b/extensions-core/datasketches/src/main/java/org/apache/druid/query/aggregation/datasketches/theta/SketchMergeAggregatorFactory.java
index d172b82bb49..2cc5388a538 100644
--- a/extensions-core/datasketches/src/main/java/org/apache/druid/query/aggregation/datasketches/theta/SketchMergeAggregatorFactory.java
+++ b/extensions-core/datasketches/src/main/java/org/apache/druid/query/aggregation/datasketches/theta/SketchMergeAggregatorFactory.java
@@ -117,9 +117,14 @@ public class SketchMergeAggregatorFactory extends SketchAggregatorFactory
    *
    * @return sketch object
    */
+  @Nullable
   @Override
-  public Object finalizeComputation(Object object)
+  public Object finalizeComputation(@Nullable Object object)
   {
+    if (object == null) {
+      return null;
+    }
+
     if (shouldFinalize) {
       SketchHolder holder = (SketchHolder) object;
       if (errorBoundsStdDev != null) {
diff --git a/extensions-core/datasketches/src/main/java/org/apache/druid/query/aggregation/datasketches/tuple/ArrayOfDoublesSketchAggregatorFactory.java b/extensions-core/datasketches/src/main/java/org/apache/druid/query/aggregation/datasketches/tuple/ArrayOfDoublesSketchAggregatorFactory.java
index 504071eb6a2..87590832f4c 100644
--- a/extensions-core/datasketches/src/main/java/org/apache/druid/query/aggregation/datasketches/tuple/ArrayOfDoublesSketchAggregatorFactory.java
+++ b/extensions-core/datasketches/src/main/java/org/apache/druid/query/aggregation/datasketches/tuple/ArrayOfDoublesSketchAggregatorFactory.java
@@ -285,10 +285,11 @@ public class ArrayOfDoublesSketchAggregatorFactory extends AggregatorFactory
     return new ArrayOfDoublesSketchAggregatorFactory(name, name, nominalEntries, null, numberOfValues);
   }
 
+  @Nullable
   @Override
-  public Object finalizeComputation(final Object object)
+  public Object finalizeComputation(@Nullable final Object object)
   {
-    return ((ArrayOfDoublesSketch) object).getEstimate();
+    return object == null ? null : ((ArrayOfDoublesSketch) object).getEstimate();
   }
 
   @Override
diff --git a/extensions-core/druid-bloom-filter/src/main/java/org/apache/druid/query/aggregation/bloom/BloomFilterAggregatorFactory.java b/extensions-core/druid-bloom-filter/src/main/java/org/apache/druid/query/aggregation/bloom/BloomFilterAggregatorFactory.java
index 74e921c3497..2c633f2dde5 100644
--- a/extensions-core/druid-bloom-filter/src/main/java/org/apache/druid/query/aggregation/bloom/BloomFilterAggregatorFactory.java
+++ b/extensions-core/druid-bloom-filter/src/main/java/org/apache/druid/query/aggregation/bloom/BloomFilterAggregatorFactory.java
@@ -227,8 +227,9 @@ public class BloomFilterAggregatorFactory extends AggregatorFactory
     }
   }
 
+  @Nullable
   @Override
-  public Object finalizeComputation(Object object)
+  public Object finalizeComputation(@Nullable Object object)
   {
     return object;
   }
diff --git a/extensions-core/histogram/src/main/java/org/apache/druid/query/aggregation/histogram/ApproximateHistogramAggregatorFactory.java b/extensions-core/histogram/src/main/java/org/apache/druid/query/aggregation/histogram/ApproximateHistogramAggregatorFactory.java
index 4c8c09a3708..ccf9c534018 100644
--- a/extensions-core/histogram/src/main/java/org/apache/druid/query/aggregation/histogram/ApproximateHistogramAggregatorFactory.java
+++ b/extensions-core/histogram/src/main/java/org/apache/druid/query/aggregation/histogram/ApproximateHistogramAggregatorFactory.java
@@ -214,10 +214,11 @@ public class ApproximateHistogramAggregatorFactory extends AggregatorFactory
     }
   }
 
+  @Nullable
   @Override
-  public Object finalizeComputation(Object object)
+  public Object finalizeComputation(@Nullable Object object)
   {
-    return ((ApproximateHistogram) object).toHistogram(numBuckets);
+    return object == null ? null : ((ApproximateHistogram) object).toHistogram(numBuckets);
   }
 
   @JsonProperty
diff --git a/extensions-core/stats/src/main/java/org/apache/druid/query/aggregation/variance/VarianceAggregatorFactory.java b/extensions-core/stats/src/main/java/org/apache/druid/query/aggregation/variance/VarianceAggregatorFactory.java
index d7e9d95eaed..fdc9cb22e69 100644
--- a/extensions-core/stats/src/main/java/org/apache/druid/query/aggregation/variance/VarianceAggregatorFactory.java
+++ b/extensions-core/stats/src/main/java/org/apache/druid/query/aggregation/variance/VarianceAggregatorFactory.java
@@ -39,6 +39,7 @@ import org.apache.druid.segment.ColumnSelectorFactory;
 import org.apache.druid.segment.ColumnValueSelector;
 import org.apache.druid.segment.NilColumnValueSelector;
 
+import javax.annotation.Nullable;
 import java.nio.ByteBuffer;
 import java.util.Collections;
 import java.util.Comparator;
@@ -202,10 +203,11 @@ public class VarianceAggregatorFactory extends AggregatorFactory
     return VarianceAggregatorCollector.COMPARATOR;
   }
 
+  @Nullable
   @Override
-  public Object finalizeComputation(Object object)
+  public Object finalizeComputation(@Nullable Object object)
   {
-    return ((VarianceAggregatorCollector) object).getVariance(isVariancePop);
+    return object == null ? null : ((VarianceAggregatorCollector) object).getVariance(isVariancePop);
   }
 
   @Override
diff --git a/processing/src/main/java/org/apache/druid/query/aggregation/CountAggregatorFactory.java b/processing/src/main/java/org/apache/druid/query/aggregation/CountAggregatorFactory.java
index 23fba55eed5..f4329fef082 100644
--- a/processing/src/main/java/org/apache/druid/query/aggregation/CountAggregatorFactory.java
+++ b/processing/src/main/java/org/apache/druid/query/aggregation/CountAggregatorFactory.java
@@ -25,6 +25,7 @@ import com.google.common.base.Preconditions;
 import com.google.common.collect.ImmutableList;
 import org.apache.druid.segment.ColumnSelectorFactory;
 
+import javax.annotation.Nullable;
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.List;
@@ -93,8 +94,9 @@ public class CountAggregatorFactory extends AggregatorFactory
     return object;
   }
 
+  @Nullable
   @Override
-  public Object finalizeComputation(Object object)
+  public Object finalizeComputation(@Nullable Object object)
   {
     return object;
   }
diff --git a/processing/src/main/java/org/apache/druid/query/aggregation/FilteredAggregatorFactory.java b/processing/src/main/java/org/apache/druid/query/aggregation/FilteredAggregatorFactory.java
index 62ee3ea91c7..52f072be085 100644
--- a/processing/src/main/java/org/apache/druid/query/aggregation/FilteredAggregatorFactory.java
+++ b/processing/src/main/java/org/apache/druid/query/aggregation/FilteredAggregatorFactory.java
@@ -32,6 +32,7 @@ import org.apache.druid.segment.column.ColumnHolder;
 import org.apache.druid.segment.filter.Filters;
 import org.joda.time.Interval;
 
+import javax.annotation.Nullable;
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.Comparator;
@@ -118,8 +119,9 @@ public class FilteredAggregatorFactory extends AggregatorFactory
     return delegate.deserialize(object);
   }
 
+  @Nullable
   @Override
-  public Object finalizeComputation(Object object)
+  public Object finalizeComputation(@Nullable Object object)
   {
     return delegate.finalizeComputation(object);
   }
diff --git a/processing/src/main/java/org/apache/druid/query/aggregation/HistogramAggregatorFactory.java b/processing/src/main/java/org/apache/druid/query/aggregation/HistogramAggregatorFactory.java
index 9ca499e0dc6..c32348dfbb3 100644
--- a/processing/src/main/java/org/apache/druid/query/aggregation/HistogramAggregatorFactory.java
+++ b/processing/src/main/java/org/apache/druid/query/aggregation/HistogramAggregatorFactory.java
@@ -154,10 +154,11 @@ public class HistogramAggregatorFactory extends AggregatorFactory
     return object;
   }
 
+  @Nullable
   @Override
-  public Object finalizeComputation(Object object)
+  public Object finalizeComputation(@Nullable Object object)
   {
-    return ((Histogram) object).asVisual();
+    return object == null ? null : ((Histogram) object).asVisual();
   }
 
   @Override
diff --git a/processing/src/main/java/org/apache/druid/query/aggregation/JavaScriptAggregatorFactory.java b/processing/src/main/java/org/apache/druid/query/aggregation/JavaScriptAggregatorFactory.java
index b5e9ed173ee..58017e7ed48 100644
--- a/processing/src/main/java/org/apache/druid/query/aggregation/JavaScriptAggregatorFactory.java
+++ b/processing/src/main/java/org/apache/druid/query/aggregation/JavaScriptAggregatorFactory.java
@@ -35,6 +35,7 @@ import org.apache.druid.segment.ColumnSelectorFactory;
 import org.apache.druid.segment.ColumnValueSelector;
 import org.checkerframework.checker.nullness.qual.EnsuresNonNull;
 import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 import org.mozilla.javascript.Context;
 import org.mozilla.javascript.ContextAction;
 import org.mozilla.javascript.ContextFactory;
@@ -202,8 +203,9 @@ public class JavaScriptAggregatorFactory extends AggregatorFactory
     return object;
   }
 
+  @Nullable
   @Override
-  public Object finalizeComputation(Object object)
+  public Object finalizeComputation(@Nullable Object object)
   {
     return object;
   }
diff --git a/processing/src/main/java/org/apache/druid/query/aggregation/SuppressedAggregatorFactory.java b/processing/src/main/java/org/apache/druid/query/aggregation/SuppressedAggregatorFactory.java
index 64dcaf08ebb..c19eb581a2d 100644
--- a/processing/src/main/java/org/apache/druid/query/aggregation/SuppressedAggregatorFactory.java
+++ b/processing/src/main/java/org/apache/druid/query/aggregation/SuppressedAggregatorFactory.java
@@ -104,8 +104,9 @@ public class SuppressedAggregatorFactory extends AggregatorFactory
     return delegate.deserialize(object);
   }
 
+  @Nullable
   @Override
-  public Object finalizeComputation(Object object)
+  public Object finalizeComputation(@Nullable Object object)
   {
     return delegate.finalizeComputation(object);
   }
diff --git a/processing/src/main/java/org/apache/druid/query/aggregation/cardinality/CardinalityAggregatorFactory.java b/processing/src/main/java/org/apache/druid/query/aggregation/cardinality/CardinalityAggregatorFactory.java
index 4647c40f825..8b619153cd4 100644
--- a/processing/src/main/java/org/apache/druid/query/aggregation/cardinality/CardinalityAggregatorFactory.java
+++ b/processing/src/main/java/org/apache/druid/query/aggregation/cardinality/CardinalityAggregatorFactory.java
@@ -44,6 +44,7 @@ import org.apache.druid.query.dimension.DimensionSpec;
 import org.apache.druid.segment.ColumnSelectorFactory;
 import org.apache.druid.segment.DimensionHandlerUtils;
 
+import javax.annotation.Nullable;
 import java.nio.ByteBuffer;
 import java.util.Collections;
 import java.util.Comparator;
@@ -234,9 +235,9 @@ public class CardinalityAggregatorFactory extends AggregatorFactory
     return HyperLogLogCollector.makeCollector(buffer);
   }
 
+  @Nullable
   @Override
-
-  public Object finalizeComputation(Object object)
+  public Object finalizeComputation(@Nullable Object object)
   {
     return HyperUniquesAggregatorFactory.estimateCardinality(object, round);
   }
diff --git a/processing/src/main/java/org/apache/druid/query/aggregation/first/StringFirstAggregatorFactory.java b/processing/src/main/java/org/apache/druid/query/aggregation/first/StringFirstAggregatorFactory.java
index 0a898bfc8e3..cceebc0cd21 100644
--- a/processing/src/main/java/org/apache/druid/query/aggregation/first/StringFirstAggregatorFactory.java
+++ b/processing/src/main/java/org/apache/druid/query/aggregation/first/StringFirstAggregatorFactory.java
@@ -36,6 +36,7 @@ import org.apache.druid.segment.BaseObjectColumnValueSelector;
 import org.apache.druid.segment.ColumnSelectorFactory;
 import org.apache.druid.segment.column.ColumnHolder;
 
+import javax.annotation.Nullable;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.Comparator;
@@ -171,10 +172,11 @@ public class StringFirstAggregatorFactory extends NullableAggregatorFactory<Base
     return new SerializablePairLongString(((Number) map.get("lhs")).longValue(), ((String) map.get("rhs")));
   }
 
+  @Nullable
   @Override
-  public Object finalizeComputation(Object object)
+  public Object finalizeComputation(@Nullable Object object)
   {
-    return ((SerializablePairLongString) object).rhs;
+    return object == null ? null : ((SerializablePairLongString) object).rhs;
   }
 
   @Override
diff --git a/processing/src/main/java/org/apache/druid/query/aggregation/hyperloglog/HyperUniquesAggregatorFactory.java b/processing/src/main/java/org/apache/druid/query/aggregation/hyperloglog/HyperUniquesAggregatorFactory.java
index e2427a6ee11..27f1650688a 100644
--- a/processing/src/main/java/org/apache/druid/query/aggregation/hyperloglog/HyperUniquesAggregatorFactory.java
+++ b/processing/src/main/java/org/apache/druid/query/aggregation/hyperloglog/HyperUniquesAggregatorFactory.java
@@ -39,6 +39,7 @@ import org.apache.druid.segment.BaseObjectColumnValueSelector;
 import org.apache.druid.segment.ColumnSelectorFactory;
 import org.apache.druid.segment.NilColumnValueSelector;
 
+import javax.annotation.Nullable;
 import java.nio.ByteBuffer;
 import java.util.Collections;
 import java.util.Comparator;
@@ -49,7 +50,7 @@ import java.util.Objects;
  */
 public class HyperUniquesAggregatorFactory extends AggregatorFactory
 {
-  public static Object estimateCardinality(Object object, boolean round)
+  public static Object estimateCardinality(@Nullable Object object, boolean round)
   {
     if (object == null) {
       return 0;
@@ -192,8 +193,9 @@ public class HyperUniquesAggregatorFactory extends AggregatorFactory
     return HyperLogLogCollector.makeCollector(buffer);
   }
 
+  @Nullable
   @Override
-  public Object finalizeComputation(Object object)
+  public Object finalizeComputation(@Nullable Object object)
   {
     return estimateCardinality(object, round);
   }
diff --git a/processing/src/main/java/org/apache/druid/query/aggregation/last/StringLastAggregatorFactory.java b/processing/src/main/java/org/apache/druid/query/aggregation/last/StringLastAggregatorFactory.java
index 4973186c376..113a1747702 100644
--- a/processing/src/main/java/org/apache/druid/query/aggregation/last/StringLastAggregatorFactory.java
+++ b/processing/src/main/java/org/apache/druid/query/aggregation/last/StringLastAggregatorFactory.java
@@ -36,6 +36,7 @@ import org.apache.druid.segment.BaseObjectColumnValueSelector;
 import org.apache.druid.segment.ColumnSelectorFactory;
 import org.apache.druid.segment.column.ColumnHolder;
 
+import javax.annotation.Nullable;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.Comparator;
@@ -129,10 +130,11 @@ public class StringLastAggregatorFactory extends NullableAggregatorFactory<BaseO
     return new SerializablePairLongString(((Number) map.get("lhs")).longValue(), ((String) map.get("rhs")));
   }
 
+  @Nullable
   @Override
-  public Object finalizeComputation(Object object)
+  public Object finalizeComputation(@Nullable Object object)
   {
-    return ((SerializablePairLongString) object).rhs;
+    return object == null ? null : ((SerializablePairLongString) object).rhs;
   }
 
   @Override