diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoTemplate.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoTemplate.java
index 81522287a..d78fbeab6 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoTemplate.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoTemplate.java
@@ -23,7 +23,6 @@ import java.math.RoundingMode;
 import java.util.*;
 import java.util.concurrent.TimeUnit;
 import java.util.function.BiPredicate;
-import java.util.function.Supplier;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
@@ -31,6 +30,7 @@ import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.bson.Document;
 import org.bson.conversions.Bson;
+
 import org.springframework.beans.BeansException;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationContextAware;
@@ -1870,21 +1870,21 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 
 	@Override
 	public <O> AggregationResults<O> aggregate(TypedAggregation<?> aggregation, Class<O> outputType) {
+
+		Assert.notNull(aggregation, "Aggregation pipeline must not be null");
 		return aggregate(aggregation, getCollectionName(aggregation.getInputType()), outputType);
 	}
 
 	@Override
 	public <O> AggregationResults<O> aggregate(TypedAggregation<?> aggregation, String inputCollectionName,
 			Class<O> outputType) {
-
-		Assert.notNull(aggregation, "Aggregation pipeline must not be null");
-
 		return aggregate(aggregation, inputCollectionName, outputType, null);
 	}
 
 	@Override
 	public <O> AggregationResults<O> aggregate(Aggregation aggregation, Class<?> inputType, Class<O> outputType) {
 
+		Assert.notNull(aggregation, "Aggregation pipeline must not be null");
 		return aggregate(aggregation, getCollectionName(inputType), outputType,
 				queryOperations.createAggregation(aggregation, inputType).getAggregationOperationContext());
 	}
@@ -1897,19 +1897,20 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 	@Override
 	public <O> Stream<O> aggregateStream(TypedAggregation<?> aggregation, String inputCollectionName,
 			Class<O> outputType) {
-
-		Assert.notNull(aggregation, "Aggregation pipeline must not be null");
 		return aggregateStream(aggregation, inputCollectionName, outputType, null);
 	}
 
 	@Override
 	public <O> Stream<O> aggregateStream(TypedAggregation<?> aggregation, Class<O> outputType) {
+
+		Assert.notNull(aggregation, "Aggregation pipeline must not be null");
 		return aggregateStream(aggregation, getCollectionName(aggregation.getInputType()), outputType);
 	}
 
 	@Override
 	public <O> Stream<O> aggregateStream(Aggregation aggregation, Class<?> inputType, Class<O> outputType) {
 
+		Assert.notNull(aggregation, "Aggregation pipeline must not be null");
 		return aggregateStream(aggregation, getCollectionName(inputType), outputType,
 				queryOperations.createAggregation(aggregation, inputType).getAggregationOperationContext());
 	}
@@ -2056,8 +2057,8 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 	protected <O> Stream<O> aggregateStream(Aggregation aggregation, String collectionName, Class<O> outputType,
 			@Nullable AggregationOperationContext context) {
 
-		Assert.hasText(collectionName, "Collection name must not be null or empty");
 		Assert.notNull(aggregation, "Aggregation pipeline must not be null");
+		Assert.hasText(collectionName, "Collection name must not be null or empty");
 		Assert.notNull(outputType, "Output type must not be null");
 		Assert.isTrue(!aggregation.getOptions().isExplain(), "Can't use explain option with streaming");
 
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveMongoTemplate.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveMongoTemplate.java
index d0102aaee..780eed57c 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveMongoTemplate.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveMongoTemplate.java
@@ -856,12 +856,13 @@ public class ReactiveMongoTemplate implements ReactiveMongoOperations, Applicati
 	public <O> Flux<O> aggregate(TypedAggregation<?> aggregation, String inputCollectionName, Class<O> outputType) {
 
 		Assert.notNull(aggregation, "Aggregation pipeline must not be null");
-
 		return doAggregate(aggregation, inputCollectionName, aggregation.getInputType(), outputType);
 	}
 
 	@Override
 	public <O> Flux<O> aggregate(TypedAggregation<?> aggregation, Class<O> outputType) {
+
+		Assert.notNull(aggregation, "Aggregation pipeline must not be null");
 		return aggregate(aggregation, getCollectionName(aggregation.getInputType()), outputType);
 	}