diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/MappingMongoConverterParser.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/MappingMongoConverterParser.java
index 69b396bdb..06fcef41f 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/MappingMongoConverterParser.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/MappingMongoConverterParser.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2016 the original author or authors.
+ * Copyright 2011-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -369,7 +369,9 @@ public class MappingMongoConverterParser implements BeanDefinitionParser {
 		 * @param filters
 		 */
 		public NegatingFilter(TypeFilter... filters) {
-			Assert.notNull(filters);
+
+			Assert.notNull(filters, "TypeFilters must not be null");
+
 			this.delegates = new HashSet<TypeFilter>(Arrays.asList(filters));
 		}
 
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/DefaultIndexOperations.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/DefaultIndexOperations.java
index 63e67d030..adf9ccbe7 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/DefaultIndexOperations.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/DefaultIndexOperations.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2016 the original author or authors.
+ * Copyright 2011-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,7 +18,6 @@ package org.springframework.data.mongodb.core;
 import static org.springframework.data.mongodb.core.MongoTemplate.*;
 
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Collection;
 import java.util.List;
 
@@ -189,7 +188,7 @@ public class DefaultIndexOperations implements IndexOperations {
 
 	public <T> T execute(CollectionCallback<T> callback) {
 
-		Assert.notNull(callback);
+		Assert.notNull(callback, "CollectionCallback must not be null!");
 
 		try {
 			MongoCollection<Document> collection = mongoDbFactory.getDb().getCollection(collectionName);
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoAdmin.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoAdmin.java
index 804ad5e59..aaa64ff27 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoAdmin.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoAdmin.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2013 the original author or authors.
+ * Copyright 2011-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -27,7 +27,8 @@ import com.mongodb.Mongo;
  * Mongo server administration exposed via JMX annotations
  * 
  * @author Mark Pollack
- * @author Thomas Darimont
+ * @author Thomas Darimont
+ * @author Mark Paluch
  */
 @ManagedResource(description = "Mongo Admin Operations")
 public class MongoAdmin implements MongoAdminOperations {
@@ -35,10 +36,11 @@ public class MongoAdmin implements MongoAdminOperations {
 	private final Mongo mongo;
 	private String username;
 	private String password;
-	private String authenticationDatabaseName;
+	private String authenticationDatabaseName;
 
 	public MongoAdmin(Mongo mongo) {
-		Assert.notNull(mongo);
+
+		Assert.notNull(mongo, "Mongo must not be null!");
 		this.mongo = mongo;
 	}
 
@@ -84,16 +86,16 @@ public class MongoAdmin implements MongoAdminOperations {
 		this.password = password;
 	}
 
-	/**
-	 * Sets the authenticationDatabaseName to use to authenticate with the Mongo database.
-	 * 
-	 * @param authenticationDatabaseName The authenticationDatabaseName to use.
-	 */
-	public void setAuthenticationDatabaseName(String authenticationDatabaseName) {
-		this.authenticationDatabaseName = authenticationDatabaseName;
-	}
-
+	/**
+	 * Sets the authenticationDatabaseName to use to authenticate with the Mongo database.
+	 * 
+	 * @param authenticationDatabaseName The authenticationDatabaseName to use.
+	 */
+	public void setAuthenticationDatabaseName(String authenticationDatabaseName) {
+		this.authenticationDatabaseName = authenticationDatabaseName;
+	}
+
 	DB getDB(String databaseName) {
-		return MongoDbUtils.getDB(mongo, databaseName, new UserCredentials(username, password), authenticationDatabaseName);
+		return MongoDbUtils.getDB(mongo, databaseName, new UserCredentials(username, password), authenticationDatabaseName);
 	}
 }
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 6fb9a0ce9..23ae2b1f9 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
@@ -218,7 +218,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 	 */
 	public MongoTemplate(MongoDbFactory mongoDbFactory, MongoConverter mongoConverter) {
 
-		Assert.notNull(mongoDbFactory);
+		Assert.notNull(mongoDbFactory, "MongoDbFactory must not be null!");
 
 		this.mongoDbFactory = mongoDbFactory;
 		this.exceptionTranslator = mongoDbFactory.getExceptionTranslator();
@@ -438,7 +438,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 	protected void executeQuery(Query query, String collectionName, DocumentCallbackHandler dch,
 			CursorPreparer preparer) {
 
-		Assert.notNull(query);
+		Assert.notNull(query, "Query must not be null!");
 
 		Document queryObject = queryMapper.getMappedObject(query.getQueryObject(), null);
 		Document sortObject = query.getSortObject();
@@ -454,7 +454,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 
 	public <T> T execute(DbCallback<T> action) {
 
-		Assert.notNull(action);
+		Assert.notNull(action, "DbCallbackmust not be null!");
 
 		try {
 			MongoDatabase db = this.getDb();
@@ -470,7 +470,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 
 	public <T> T execute(String collectionName, CollectionCallback<T> callback) {
 
-		Assert.notNull(callback);
+		Assert.notNull(callback, "CollectionCallback must not be null!");
 
 		try {
 			MongoCollection<Document> collection = getAndPrepareCollection(getDb(), collectionName);
@@ -735,7 +735,8 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 	}
 
 	public long count(Query query, Class<?> entityClass) {
-		Assert.notNull(entityClass);
+
+		Assert.notNull(entityClass, "Entity class must not be null!");
 		return count(query, entityClass, determineCollectionName(entityClass));
 	}
 
@@ -749,7 +750,8 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 	 */
 	public long count(Query query, Class<?> entityClass, String collectionName) {
 
-		Assert.hasText(collectionName);
+		Assert.hasText(collectionName, "Collection name must not be null or empty!");
+
 		final Document document = query == null ? null
 				: queryMapper.getMappedObject(query.getQueryObject(),
 						entityClass == null ? null : mappingContext.getPersistentEntity(entityClass));
@@ -932,7 +934,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 
 	protected <T> void doInsertBatch(String collectionName, Collection<? extends T> batchToSave, MongoWriter<T> writer) {
 
-		Assert.notNull(writer);
+		Assert.notNull(writer, "MongoWriter must not be null!");
 
 		List<Document> documentList = new ArrayList<Document>();
 		for (T o : batchToSave) {
@@ -960,14 +962,14 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 
 	public void save(Object objectToSave) {
 
-		Assert.notNull(objectToSave);
+		Assert.notNull(objectToSave, "Object to save must not be null!");
 		save(objectToSave, determineEntityCollectionName(objectToSave));
 	}
 
 	public void save(Object objectToSave, String collectionName) {
 
-		Assert.notNull(objectToSave);
-		Assert.hasText(collectionName);
+		Assert.notNull(objectToSave, "Object to save must not be null!");
+		Assert.hasText(collectionName, "Collection name must not be null or empty!");
 
 		MongoPersistentEntity<?> mongoPersistentEntity = getPersistentEntity(objectToSave.getClass());
 
@@ -1240,7 +1242,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 
 	public DeleteResult remove(Object object, String collection) {
 
-		Assert.hasText(collection);
+		Assert.hasText(collection, "Collection name must not be null or empty!");
 
 		if (object == null) {
 			return null;
@@ -2348,8 +2350,9 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 
 		public ReadDocumentCallback(EntityReader<? super T, Bson> reader, Class<T> type, String collectionName) {
 
-			Assert.notNull(reader);
-			Assert.notNull(type);
+			Assert.notNull(reader, "EntityReader must not be null!");
+			Assert.notNull(type, "Entity type must not be null!");
+
 			this.reader = reader;
 			this.type = type;
 			this.collectionName = collectionName;
@@ -2491,7 +2494,9 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 		 * @param delegate must not be {@literal null}.
 		 */
 		public GeoNearResultDocumentCallback(DocumentCallback<T> delegate, Metric metric) {
-			Assert.notNull(delegate);
+
+			Assert.notNull(delegate, "DocumentCallback must not be null!");
+
 			this.delegate = delegate;
 			this.metric = metric;
 		}
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 b3f9bc7aa..c13bae356 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
@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 the original author or authors.
+ * Copyright 2016-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -373,7 +373,8 @@ public class ReactiveMongoTemplate implements ReactiveMongoOperations, Applicati
 	 * @see org.springframework.data.mongodb.core.ReactiveMongoOperations#execute(java.lang.String, org.springframework.data.mongodb.core.ReactiveCollectionCallback)
 	 */
 	public <T> Flux<T> execute(String collectionName, ReactiveCollectionCallback<T> callback) {
-		Assert.notNull(callback);
+
+		Assert.notNull(callback, "ReactiveCollectionCallback must not be null!");
 		return createFlux(collectionName, callback);
 	}
 
@@ -386,7 +387,7 @@ public class ReactiveMongoTemplate implements ReactiveMongoOperations, Applicati
 	 */
 	public <T> Flux<T> createFlux(ReactiveDatabaseCallback<T> callback) {
 
-		Assert.notNull(callback);
+		Assert.notNull(callback, "ReactiveDatabaseCallback must not be null!");
 
 		return Flux.defer(() -> callback.doInDB(getMongoDatabase())).onErrorResumeWith(translateFluxException());
 	}
@@ -400,7 +401,7 @@ public class ReactiveMongoTemplate implements ReactiveMongoOperations, Applicati
 	 */
 	public <T> Mono<T> createMono(final ReactiveDatabaseCallback<T> callback) {
 
-		Assert.notNull(callback);
+		Assert.notNull(callback, "ReactiveDatabaseCallback must not be null!");
 
 		return Mono.defer(() -> Mono.from(callback.doInDB(getMongoDatabase()))).otherwise(translateMonoException());
 	}
@@ -414,8 +415,8 @@ public class ReactiveMongoTemplate implements ReactiveMongoOperations, Applicati
 	 */
 	public <T> Flux<T> createFlux(String collectionName, ReactiveCollectionCallback<T> callback) {
 
-		Assert.hasText(collectionName);
-		Assert.notNull(callback);
+		Assert.hasText(collectionName, "Collection name must not be null or empty!");
+		Assert.notNull(callback, "ReactiveDatabaseCallback must not be null!");
 
 		Mono<MongoCollection<Document>> collectionPublisher = Mono
 				.fromCallable(() -> getAndPrepareCollection(getMongoDatabase(), collectionName));
@@ -433,8 +434,8 @@ public class ReactiveMongoTemplate implements ReactiveMongoOperations, Applicati
 	 */
 	public <T> Mono<T> createMono(String collectionName, ReactiveCollectionCallback<T> callback) {
 
-		Assert.hasText(collectionName);
-		Assert.notNull(callback);
+		Assert.hasText(collectionName, "Collection name must not be null or empty!");
+		Assert.notNull(callback, "ReactiveCollectionCallback must not be null!");
 
 		Mono<MongoCollection<Document>> collectionPublisher = Mono
 				.fromCallable(() -> getAndPrepareCollection(getMongoDatabase(), collectionName));
@@ -729,7 +730,9 @@ public class ReactiveMongoTemplate implements ReactiveMongoOperations, Applicati
 	 * @see org.springframework.data.mongodb.core.ReactiveMongoOperations#count(org.springframework.data.mongodb.core.query.Query, java.lang.Class)
 	 */
 	public Mono<Long> count(Query query, Class<?> entityClass) {
-		Assert.notNull(entityClass);
+
+		Assert.notNull(entityClass, "Entity class must not be null!");
+
 		return count(query, entityClass, determineCollectionName(entityClass));
 	}
 
@@ -745,7 +748,7 @@ public class ReactiveMongoTemplate implements ReactiveMongoOperations, Applicati
 	 */
 	public Mono<Long> count(final Query query, final Class<?> entityClass, String collectionName) {
 
-		Assert.hasText(collectionName);
+		Assert.hasText(collectionName, "Collection name must not be null or empty!");
 
 		return createMono(collectionName, collection -> {
 
@@ -880,7 +883,7 @@ public class ReactiveMongoTemplate implements ReactiveMongoOperations, Applicati
 	protected <T> Flux<T> doInsertBatch(final String collectionName, final Collection<? extends T> batchToSave,
 			final MongoWriter<Object> writer) {
 
-		Assert.notNull(writer);
+		Assert.notNull(writer, "MongoWriter must not be null!");
 
 		Mono<List<Tuple2<T, Document>>> prepareDocuments = Flux.fromIterable(batchToSave)
 				.flatMap(new Function<T, Flux<Tuple2<T, Document>>>() {
@@ -933,7 +936,7 @@ public class ReactiveMongoTemplate implements ReactiveMongoOperations, Applicati
 	 */
 	public <T> Mono<T> save(T objectToSave) {
 
-		Assert.notNull(objectToSave);
+		Assert.notNull(objectToSave, "Object to save must not be null!");
 		return save(objectToSave, determineEntityCollectionName(objectToSave));
 	}
 
@@ -942,8 +945,8 @@ public class ReactiveMongoTemplate implements ReactiveMongoOperations, Applicati
 	 */
 	public <T> Mono<T> save(T objectToSave, String collectionName) {
 
-		Assert.notNull(objectToSave);
-		Assert.hasText(collectionName);
+		Assert.notNull(objectToSave, "Object to save must not be null!");
+		Assert.hasText(collectionName, "Collection name must not be null or empty!");
 
 		MongoPersistentEntity<?> mongoPersistentEntity = getPersistentEntity(objectToSave.getClass());
 
@@ -1275,7 +1278,7 @@ public class ReactiveMongoTemplate implements ReactiveMongoOperations, Applicati
 	 */
 	public Mono<DeleteResult> remove(Object object, String collection) {
 
-		Assert.hasText(collection);
+		Assert.hasText(collection, "Collection name must not be null or empty!");
 
 		if (object == null) {
 			return null;
@@ -1839,7 +1842,7 @@ public class ReactiveMongoTemplate implements ReactiveMongoOperations, Applicati
 
 	private <T> T execute(MongoDatabaseCallback<T> action) {
 
-		Assert.notNull(action);
+		Assert.notNull(action, "MongoDatabaseCallback must not be null!");
 
 		try {
 			MongoDatabase db = this.getMongoDatabase();
@@ -2202,8 +2205,9 @@ public class ReactiveMongoTemplate implements ReactiveMongoOperations, Applicati
 
 		ReadDocumentCallback(EntityReader<? super T, Bson> reader, Class<T> type, String collectionName) {
 
-			Assert.notNull(reader);
-			Assert.notNull(type);
+			Assert.notNull(reader, "EntityReader must not be null!");
+			Assert.notNull(type, "Entity type must not be null!");
+
 			this.reader = reader;
 			this.type = type;
 			this.collectionName = collectionName;
@@ -2240,7 +2244,8 @@ public class ReactiveMongoTemplate implements ReactiveMongoOperations, Applicati
 		 */
 		GeoNearResultDbObjectCallback(DocumentCallback<T> delegate, Metric metric) {
 
-			Assert.notNull(delegate);
+			Assert.notNull(delegate, "DocumentCallback must not be null!");
+
 			this.delegate = delegate;
 			this.metric = metric;
 		}
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AggregationResults.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AggregationResults.java
index dec351601..c45d34a82 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AggregationResults.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AggregationResults.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2016 the original author or authors.
+ * Copyright 2013-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -29,6 +29,7 @@ import org.springframework.util.Assert;
  * @author Oliver Gierke
  * @author Thomas Darimont
  * @author Christoph Strobl
+ * @author Mark Paluch
  * @param <T> The class in which the results are mapped onto.
  * @since 1.3
  */
@@ -46,8 +47,8 @@ public class AggregationResults<T> implements Iterable<T> {
 	 */
 	public AggregationResults(List<T> mappedResults, Document rawResults) {
 
-		Assert.notNull(mappedResults);
-		Assert.notNull(rawResults);
+		Assert.notNull(mappedResults, "List of mapped results must not be null!");
+		Assert.notNull(rawResults, "Raw results must not be null!");
 
 		this.mappedResults = Collections.unmodifiableList(mappedResults);
 		this.rawResults = rawResults;
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/ConverterRegistration.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/ConverterRegistration.java
index 3365c2359..133d778a5 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/ConverterRegistration.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/ConverterRegistration.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2011 the original author or authors.
+ * Copyright 2011-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -23,6 +23,7 @@ import org.springframework.util.Assert;
  * Conversion registration information.
  * 
  * @author Oliver Gierke
+ * @author Mark Paluch
  */
 class ConverterRegistration {
 
@@ -39,7 +40,7 @@ class ConverterRegistration {
 	 */
 	public ConverterRegistration(ConvertiblePair convertiblePair, boolean isReading, boolean isWriting) {
 
-		Assert.notNull(convertiblePair);
+		Assert.notNull(convertiblePair, "ConvertiblePair must not be null!");
 
 		this.convertiblePair = convertiblePair;
 		this.reading = isReading;
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/CustomConversions.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/CustomConversions.java
index e57c92a6c..ffea59ed5 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/CustomConversions.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/CustomConversions.java
@@ -89,7 +89,7 @@ public class CustomConversions {
 	 */
 	public CustomConversions(List<?> converters) {
 
-		Assert.notNull(converters);
+		Assert.notNull(converters, "List of converters must not be null!");
 
 		this.readingPairs = new LinkedHashSet<ConvertiblePair>();
 		this.writingPairs = new LinkedHashSet<ConvertiblePair>();
@@ -346,8 +346,8 @@ public class CustomConversions {
 	private static Class<?> getCustomTarget(Class<?> sourceType, Class<?> requestedTargetType,
 			Collection<ConvertiblePair> pairs) {
 
-		Assert.notNull(sourceType);
-		Assert.notNull(pairs);
+		Assert.notNull(sourceType, "Source Class must not be null!");
+		Assert.notNull(pairs, "Collection of ConvertiblePair must not be null!");
 
 		if (requestedTargetType != null && pairs.contains(new ConvertiblePair(sourceType, requestedTargetType))) {
 			return requestedTargetType;
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/MappingMongoConverter.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/MappingMongoConverter.java
index 1fb169435..f7557f30b 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/MappingMongoConverter.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/MappingMongoConverter.java
@@ -1,11 +1,11 @@
 /*
- * Copyright 2011-2017 by the original author(s).
+ * Copyright 2011-2017 the original author or authors.
  *
  * Licensed 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
+ *      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,
@@ -326,7 +326,7 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 		return result;
 	}
 
-	/* 
+	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.mongodb.core.convert.MongoWriter#toDBRef(java.lang.Object, org.springframework.data.mongodb.core.mapping.MongoPersistentProperty)
 	 */
@@ -497,7 +497,7 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 			DBRef dbRefObj = null;
 
 			/*
-			 * If we already have a LazyLoadingProxy, we use it's cached DBRef value instead of 
+			 * If we already have a LazyLoadingProxy, we use it's cached DBRef value instead of
 			 * unnecessarily initializing it only to convert it to a DBRef a few instructions later.
 			 */
 			if (obj instanceof LazyLoadingProxy) {
@@ -851,7 +851,7 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 
 	protected DBRef createDBRef(Object target, MongoPersistentProperty property) {
 
-		Assert.notNull(target);
+		Assert.notNull(target, "Target object must not be null!");
 
 		if (target instanceof DBRef) {
 			return (DBRef) target;
@@ -1172,7 +1172,7 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 
 	/**
 	 * Removes the type information from the entire conversion result.
-	 * 
+	 *
 	 * @param object
 	 * @param recursively whether to apply the removal recursively
 	 * @return
@@ -1237,22 +1237,22 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 		/**
 		 * Creates a new {@link MongoDbPropertyValueProvider} for the given source, {@link SpELExpressionEvaluator} and
 		 * {@link ObjectPath}.
-		 * 
+		 *
 		 * @param source must not be {@literal null}.
 		 * @param evaluator must not be {@literal null}.
 		 * @param path can be {@literal null}.
 		 */
 		public MongoDbPropertyValueProvider(Bson source, SpELExpressionEvaluator evaluator, ObjectPath path) {
 
-			Assert.notNull(source);
-			Assert.notNull(evaluator);
+			Assert.notNull(source, "Bson source must not be null!");
+			Assert.notNull(evaluator, "SpELExpressionEvaluator must not be null!");
 
 			this.source = new DocumentAccessor(source);
 			this.evaluator = evaluator;
 			this.path = path;
 		}
 
-		/* 
+		/*
 		 * (non-Javadoc)
 		 * @see org.springframework.data.convert.PropertyValueProvider#getPropertyValue(org.springframework.data.mapping.PersistentProperty)
 		 */
@@ -1295,7 +1295,7 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 			this.path = path;
 		}
 
-		/* 
+		/*
 		 * (non-Javadoc)
 		 * @see org.springframework.data.mapping.model.SpELExpressionParameterValueProvider#potentiallyConvertSpelValue(java.lang.Object, org.springframework.data.mapping.PreferredConstructor.Parameter)
 		 */
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/QueryMapper.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/QueryMapper.java
index 492cb870a..a00b48dde 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/QueryMapper.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/QueryMapper.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2016 the original author or authors.
+ * Copyright 2011-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -86,7 +86,7 @@ public class QueryMapper {
 	 */
 	public QueryMapper(MongoConverter converter) {
 
-		Assert.notNull(converter);
+		Assert.notNull(converter, "MongoConverter must not be null!");
 
 		this.conversionService = converter.getConversionService();
 		this.converter = converter;
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/geo/Sphere.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/geo/Sphere.java
index 0cb623ef2..ccfb41d3c 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/geo/Sphere.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/geo/Sphere.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2014 the original author or authors.
+ * Copyright 2014-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -29,6 +29,7 @@ import org.springframework.util.Assert;
  * Represents a geospatial sphere value.
  * 
  * @author Thomas Darimont
+ * @author Mark Paluch
  * @since 1.5
  */
 public class Sphere implements Shape {
@@ -46,8 +47,8 @@ public class Sphere implements Shape {
 	@PersistenceConstructor
 	public Sphere(Point center, Distance radius) {
 
-		Assert.notNull(center);
-		Assert.notNull(radius);
+		Assert.notNull(center, "Center point must not be null!");
+		Assert.notNull(radius, "Radius must not be null!");
 		Assert.isTrue(radius.getValue() >= 0, "Radius must not be negative!");
 
 		this.center = center;
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/IndexField.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/IndexField.java
index 8bf243ee7..dd74cf365 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/IndexField.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/IndexField.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2014 the original author or authors.
+ * Copyright 2012-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -43,8 +43,13 @@ public final class IndexField {
 
 	private IndexField(String key, Direction direction, Type type, Float weight) {
 
-		Assert.hasText(key);
-		Assert.isTrue(direction != null ^ (Type.GEO.equals(type) || Type.TEXT.equals(type)));
+		Assert.hasText(key, "Key must not be null or empty");
+
+		if (Type.GEO.equals(type) || Type.TEXT.equals(type)) {
+			Assert.isTrue(direction == null, "Geo/Text indexes must not have a direction!");
+		} else {
+			Assert.notNull(direction, "Default indexes require a direction");
+		}
 
 		this.key = key;
 		this.direction = direction;
@@ -53,7 +58,9 @@ public final class IndexField {
 	}
 
 	public static IndexField create(String key, Direction order) {
-		Assert.notNull(order);
+		
+		Assert.notNull(order, "Direction must not be null!");
+
 		return new IndexField(key, order, Type.DEFAULT);
 	}
 
@@ -102,7 +109,7 @@ public final class IndexField {
 	}
 
 	/**
-	 * Returns wheter the {@link IndexField} is a text index field.
+	 * Returns whether the {@link IndexField} is a text index field.
 	 * 
 	 * @return true if type is {@link Type#TEXT}
 	 * @since 1.6
@@ -132,7 +139,7 @@ public final class IndexField {
 				&& this.type == that.type;
 	}
 
-	/* 
+	/*
 	 * (non-Javadoc)
 	 * @see java.lang.Object#hashCode()
 	 */
@@ -147,7 +154,7 @@ public final class IndexField {
 		return result;
 	}
 
-	/* 
+	/*
 	 * (non-Javadoc)
 	 * @see java.lang.Object#toString()
 	 */
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/IndexInfo.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/IndexInfo.java
index 67c60d45d..f74c69439 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/IndexInfo.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/IndexInfo.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -23,17 +23,15 @@ import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 
-import com.mongodb.DBObject;
 import org.bson.Document;
 import org.springframework.util.Assert;
 import org.springframework.util.ObjectUtils;
 
-import com.mongodb.DBObject;
-
 /**
  * @author Mark Pollack
  * @author Oliver Gierke
  * @author Christoph Strobl
+ * @author Mark Paluch
  */
 public class IndexInfo {
 
@@ -132,7 +130,8 @@ public class IndexInfo {
 	 */
 	public boolean isIndexForFields(Collection<String> keys) {
 
-		Assert.notNull(keys);
+		Assert.notNull(keys, "Collection of keys must not be null!");
+
 		List<String> indexKeys = new ArrayList<String>(indexFields.size());
 
 		for (IndexField field : indexFields) {
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/MongoMappingEventPublisher.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/MongoMappingEventPublisher.java
index 26ce21680..4f19ebd6c 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/MongoMappingEventPublisher.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/MongoMappingEventPublisher.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2015 the original author or authors.
+ * Copyright 2011-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -34,6 +34,7 @@ import org.springframework.util.Assert;
  * 
  * @author Jon Brisbin
  * @author Oliver Gierke
+ * @author Mark Paluch
  */
 public class MongoMappingEventPublisher implements ApplicationEventPublisher {
 
@@ -46,7 +47,7 @@ public class MongoMappingEventPublisher implements ApplicationEventPublisher {
 	 */
 	public MongoMappingEventPublisher(MongoPersistentEntityIndexCreator indexCreator) {
 
-		Assert.notNull(indexCreator);
+		Assert.notNull(indexCreator, "MongoPersistentEntityIndexCreator must not be null!");
 		this.indexCreator = indexCreator;
 	}
 
@@ -61,7 +62,7 @@ public class MongoMappingEventPublisher implements ApplicationEventPublisher {
 		}
 	}
 
-	/* 
+	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.context.ApplicationEventPublisher#publishEvent(java.lang.Object)
 	 */
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/MongoPersistentEntityIndexCreator.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/MongoPersistentEntityIndexCreator.java
index 007f9dc66..a1a31e68d 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/MongoPersistentEntityIndexCreator.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/MongoPersistentEntityIndexCreator.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2016 the original author or authors.
+ * Copyright 2011-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -23,7 +23,6 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.context.ApplicationListener;
 import org.springframework.dao.DataIntegrityViolationException;
-import org.springframework.dao.support.PersistenceExceptionTranslator;
 import org.springframework.data.mapping.PersistentEntity;
 import org.springframework.data.mapping.context.MappingContext;
 import org.springframework.data.mapping.context.MappingContextEvent;
@@ -82,9 +81,10 @@ public class MongoPersistentEntityIndexCreator implements ApplicationListener<Ma
 	 */
 	public MongoPersistentEntityIndexCreator(MongoMappingContext mappingContext, IndexOperationsProvider indexOperationsProvider,
 											 IndexResolver indexResolver) {
-		Assert.notNull(indexOperationsProvider);
-		Assert.notNull(mappingContext);
-		Assert.notNull(indexResolver);
+
+		Assert.notNull(mappingContext, "MongoMappingContext must not be null!");
+		Assert.notNull(indexOperationsProvider, "IndexOperationsProvider must not be null!");
+		Assert.notNull(indexResolver, "IndexResolver must not be null!");
 
 		this.indexOperationsProvider = indexOperationsProvider;
 		this.mappingContext = mappingContext;
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/BasicMongoPersistentEntity.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/BasicMongoPersistentEntity.java
index a1196fca4..71734ecc4 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/BasicMongoPersistentEntity.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/BasicMongoPersistentEntity.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2014 the original author or authors.
+ * Copyright 2011-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -51,6 +51,7 @@ import org.springframework.util.StringUtils;
  * @author Oliver Gierke
  * @author Thomas Darimont
  * @author Christoph Strobl
+ * @author Mark Paluch
  */
 public class BasicMongoPersistentEntity<T> extends BasicPersistentEntity<T, MongoPersistentProperty> implements
 		MongoPersistentEntity<T>, ApplicationContextAware {
@@ -138,7 +139,7 @@ public class BasicMongoPersistentEntity<T> extends BasicPersistentEntity<T, Mong
 		return getTextScoreProperty() != null;
 	}
 
-	/* 
+	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.mapping.model.BasicPersistentEntity#verify()
 	 */
@@ -200,7 +201,7 @@ public class BasicMongoPersistentEntity<T> extends BasicPersistentEntity<T, Mong
 	@Override
 	protected MongoPersistentProperty returnPropertyIfBetterIdPropertyCandidateOrNull(MongoPersistentProperty property) {
 
-		Assert.notNull(property);
+		Assert.notNull(property, "MongoPersistentProperty must not be null!");
 
 		if (!property.isIdProperty()) {
 			return null;
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapreduce/GroupByResults.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapreduce/GroupByResults.java
index 1b4e9db0f..3fb89c703 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapreduce/GroupByResults.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapreduce/GroupByResults.java
@@ -1,11 +1,11 @@
 /*
- * Copyright 2011 - 2016O the original author or authors.
+ * Copyright 2011-2017 the original author or authors.
  *
  * Licensed 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
+ *      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,
@@ -26,6 +26,7 @@ import org.springframework.util.Assert;
  * 
  * @author Mark Pollack
  * @author Christoph Strobl
+ * @author Mark Paluch
  * @param <T> The class in which the results are mapped onto, accessible via an {@link Iterator}.
  */
 public class GroupByResults<T> implements Iterable<T> {
@@ -39,10 +40,12 @@ public class GroupByResults<T> implements Iterable<T> {
 
 	public GroupByResults(List<T> mappedResults, Document rawResults) {
 
-		Assert.notNull(mappedResults);
-		Assert.notNull(rawResults);
+		Assert.notNull(mappedResults, "List of mapped results must not be null!");
+		Assert.notNull(rawResults, "Raw results must not be null!");
+
 		this.mappedResults = mappedResults;
 		this.rawResults = rawResults;
+
 		parseKeys();
 		parseCount();
 		parseServerUsed();
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapreduce/MapReduceResults.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapreduce/MapReduceResults.java
index 983498f4c..bb7d21bdd 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapreduce/MapReduceResults.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapreduce/MapReduceResults.java
@@ -1,11 +1,11 @@
 /*
- * Copyright 2011-2016 the original author or authors.
+ * Copyright 2011-2017 the original author or authors.
  *
  * Licensed 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
+ *      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,
@@ -29,6 +29,7 @@ import com.mongodb.MapReduceOutput;
  * @author Mark Pollack
  * @author Oliver Gierke
  * @author Christoph Strobl
+ * @author Mark Paluch
  * @param <T> The class in which the results are mapped onto, accessible via an iterator.
  */
 public class MapReduceResults<T> implements Iterable<T> {
@@ -49,8 +50,8 @@ public class MapReduceResults<T> implements Iterable<T> {
 	@Deprecated
 	public MapReduceResults(List<T> mappedResults, Document rawResults) {
 
-		Assert.notNull(mappedResults);
-		Assert.notNull(rawResults);
+		Assert.notNull(mappedResults, "List of mapped results must not be null!");
+		Assert.notNull(rawResults, "Raw results must not be null!");
 
 		this.mappedResults = mappedResults;
 		this.rawResults = rawResults;
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/query/Criteria.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/query/Criteria.java
index dd2a10476..27f5856ce 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/query/Criteria.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/query/Criteria.java
@@ -50,6 +50,7 @@ import com.mongodb.BasicDBList;
  * @author Oliver Gierke
  * @author Thomas Darimont
  * @author Christoph Strobl
+ * @author Mark Paluch
  */
 public class Criteria implements CriteriaDefinition {
 
@@ -386,7 +387,7 @@ public class Criteria implements CriteriaDefinition {
 	 */
 	public Criteria regex(Pattern pattern) {
 
-		Assert.notNull(pattern);
+		Assert.notNull(pattern, "Pattern must not be null!");
 
 		if (lastOperatorWasNot()) {
 			return not(pattern);
@@ -407,7 +408,9 @@ public class Criteria implements CriteriaDefinition {
 	}
 
 	private Pattern toPattern(String regex, String options) {
-		Assert.notNull(regex);
+
+		Assert.notNull(regex, "Regex string must not be null!");
+
 		return Pattern.compile(regex, options == null ? 0 : BSON.regexFlags(options));
 	}
 
@@ -421,7 +424,9 @@ public class Criteria implements CriteriaDefinition {
 	 * @see <a href="https://docs.mongodb.com/manual/reference/operator/query/centerSphere/">MongoDB Query operator: $centerSphere</a>
 	 */
 	public Criteria withinSphere(Circle circle) {
-		Assert.notNull(circle);
+
+		Assert.notNull(circle, "Circle must not be null!");
+
 		criteria.put("$geoWithin", new GeoCommand(new Sphere(circle)));
 		return this;
 	}
@@ -435,7 +440,8 @@ public class Criteria implements CriteriaDefinition {
 	 */
 	public Criteria within(Shape shape) {
 
-		Assert.notNull(shape);
+		Assert.notNull(shape, "Shape must not be null!");
+
 		criteria.put("$geoWithin", new GeoCommand(shape));
 		return this;
 	}
@@ -448,7 +454,9 @@ public class Criteria implements CriteriaDefinition {
 	 * @see <a href="https://docs.mongodb.com/manual/reference/operator/query/near/">MongoDB Query operator: $near</a>
 	 */
 	public Criteria near(Point point) {
-		Assert.notNull(point);
+
+		Assert.notNull(point, "Point must not be null!");
+
 		criteria.put("$near", point);
 		return this;
 	}
@@ -462,7 +470,9 @@ public class Criteria implements CriteriaDefinition {
 	 * @see <a href="https://docs.mongodb.com/manual/reference/operator/query/nearSphere/">MongoDB Query operator: $nearSphere</a>
 	 */
 	public Criteria nearSphere(Point point) {
-		Assert.notNull(point);
+
+		Assert.notNull(point, "Point must not be null!");
+
 		criteria.put("$nearSphere", point);
 		return this;
 	}
@@ -716,7 +726,7 @@ public class Criteria implements CriteriaDefinition {
 		return false;
 	}
 
-	/* 
+	/*
 	 * (non-Javadoc)
 	 * @see java.lang.Object#equals(java.lang.Object)
 	 */
@@ -779,7 +789,7 @@ public class Criteria implements CriteriaDefinition {
 		return ObjectUtils.nullSafeEquals(left, right);
 	}
 
-	/* 
+	/*
 	 * (non-Javadoc)
 	 * @see java.lang.Object#hashCode()
 	 */
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/query/NearQuery.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/query/NearQuery.java
index ec2fd0609..add50e92a 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/query/NearQuery.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/query/NearQuery.java
@@ -1,11 +1,11 @@
 /*
- * Copyright 2011-2016 the original author or authors.
+ * Copyright 2011-2017 the original author or authors.
  *
  * Licensed 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
+ *      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,
@@ -47,11 +47,11 @@ public final class NearQuery {
 	/**
 	 * Creates a new {@link NearQuery}.
 	 * 
-	 * @param point
+	 * @param point must not be {@literal null}.
 	 */
 	private NearQuery(Point point, Metric metric) {
 
-		Assert.notNull(point);
+		Assert.notNull(point, "Point must not be null!");
 
 		this.point = point;
 		this.spherical = false;
@@ -106,7 +106,6 @@ public final class NearQuery {
 	 * @return
 	 */
 	public static NearQuery near(Point point, Metric metric) {
-		Assert.notNull(point);
 		return new NearQuery(point, metric);
 	}
 
@@ -183,7 +182,8 @@ public final class NearQuery {
 	 */
 	public NearQuery maxDistance(double maxDistance, Metric metric) {
 
-		Assert.notNull(metric);
+		Assert.notNull(metric, "Metric must not be null!");
+
 		return maxDistance(new Distance(maxDistance, metric));
 	}
 
@@ -196,7 +196,7 @@ public final class NearQuery {
 	 */
 	public NearQuery maxDistance(Distance distance) {
 
-		Assert.notNull(distance);
+		Assert.notNull(distance, "Distance must not be null!");
 
 		if (distance.getMetric() != Metrics.NEUTRAL) {
 			this.spherical(true);
@@ -239,7 +239,8 @@ public final class NearQuery {
 	 */
 	public NearQuery minDistance(double minDistance, Metric metric) {
 
-		Assert.notNull(metric);
+		Assert.notNull(metric, "Metric must not be null!");
+
 		return minDistance(new Distance(minDistance, metric));
 	}
 
@@ -253,7 +254,7 @@ public final class NearQuery {
 	 */
 	public NearQuery minDistance(Distance distance) {
 
-		Assert.notNull(distance);
+		Assert.notNull(distance, "Distance must not be null!");
 
 		if (distance.getMetric() != Metrics.NEUTRAL) {
 			this.spherical(true);
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/spel/ExpressionNode.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/spel/ExpressionNode.java
index 01c7c1810..9fb3f5b89 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/spel/ExpressionNode.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/spel/ExpressionNode.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2016 the original author or authors.
+ * Copyright 2013-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -31,6 +31,7 @@ import org.springframework.util.Assert;
  * 
  * @author Oliver Gierke
  * @author Christoph Strobl
+ * @author Mark Paluch
  */
 public class ExpressionNode implements Iterable<ExpressionNode> {
 
@@ -173,7 +174,7 @@ public class ExpressionNode implements Iterable<ExpressionNode> {
 	 */
 	public ExpressionNode getChild(int index) {
 
-		Assert.isTrue(index >= 0);
+		Assert.isTrue(index >= 0, "Index must be greater or equal to zero!");
 		return from(node.getChild(index), state);
 	}
 
@@ -199,7 +200,7 @@ public class ExpressionNode implements Iterable<ExpressionNode> {
 		return from(node, state);
 	}
 
-	/* 
+	/*
 	 * (non-Javadoc)
 	 * @see java.lang.Iterable#iterator()
 	 */
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/gridfs/AntPath.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/gridfs/AntPath.java
index de20bc35d..a9fa8f84b 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/gridfs/AntPath.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/gridfs/AntPath.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2011 the original author or authors.
+ * Copyright 2011-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -24,6 +24,7 @@ import org.springframework.util.Assert;
  * Value object to abstract Ant paths.
  * 
  * @author Oliver Gierke
+ * @author Mark Paluch
  */
 class AntPath {
 
@@ -38,7 +39,9 @@ class AntPath {
 	 * @param path must not be {@literal null}.
 	 */
 	public AntPath(String path) {
-		Assert.notNull(path);
+
+		Assert.notNull(path, "Path must not be null!");
+
 		this.path = path;
 	}
 
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/gridfs/GridFsTemplate.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/gridfs/GridFsTemplate.java
index 223941dfd..ebb10588b 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/gridfs/GridFsTemplate.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/gridfs/GridFsTemplate.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2016 the original author or authors.
+ * Copyright 2011-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -48,6 +48,7 @@ import com.mongodb.client.gridfs.model.GridFSUploadOptions;
  * @author Thomas Darimont
  * @author Martin Baumgartner
  * @author Christoph Strobl
+ * @author Mark Paluch
  */
 public class GridFsTemplate implements GridFsOperations, ResourcePatternResolver {
 
@@ -75,8 +76,8 @@ public class GridFsTemplate implements GridFsOperations, ResourcePatternResolver
 	 */
 	public GridFsTemplate(MongoDbFactory dbFactory, MongoConverter converter, String bucket) {
 
-		Assert.notNull(dbFactory);
-		Assert.notNull(converter);
+		Assert.notNull(dbFactory, "MongoDbFactory must not be null!");
+		Assert.notNull(converter, "MongoConverter must not be null!");
 
 		this.dbFactory = dbFactory;
 		this.converter = converter;
@@ -158,7 +159,7 @@ public class GridFsTemplate implements GridFsOperations, ResourcePatternResolver
 	 */
 	public ObjectId store(InputStream content, String filename, String contentType, Document metadata) {
 
-		Assert.notNull(content);
+		Assert.notNull(content, "InputStream must not be null!");
 
 		GridFSUploadOptions opts = new GridFSUploadOptions();
 
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/cdi/MongoRepositoryBean.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/cdi/MongoRepositoryBean.java
index 0a43c72b2..6a43fa025 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/cdi/MongoRepositoryBean.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/cdi/MongoRepositoryBean.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2014 the original author or authors.
+ * Copyright 2012-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -53,11 +53,11 @@ public class MongoRepositoryBean<T> extends CdiRepositoryBean<T> {
 
 		super(qualifiers, repositoryType, beanManager, detector);
 
-		Assert.notNull(operations);
+		Assert.notNull(operations, "MongoOperations bean must not be null!");
 		this.operations = operations;
 	}
 
-	/* 
+	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.repository.cdi.CdiRepositoryBean#create(javax.enterprise.context.spi.CreationalContext, java.lang.Class)
 	 */
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/query/ConvertingParameterAccessor.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/query/ConvertingParameterAccessor.java
index 15d0cd25e..f49f4d69d 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/query/ConvertingParameterAccessor.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/query/ConvertingParameterAccessor.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2015 the original author or authors.
+ * Copyright 2011-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -42,6 +42,7 @@ import com.mongodb.DBRef;
  * @author Oliver Gierke
  * @author Christoph Strobl
  * @author Thomas Darimont
+ * @author Mark Paluch
  */
 public class ConvertingParameterAccessor implements MongoParameterAccessor {
 
@@ -56,41 +57,41 @@ public class ConvertingParameterAccessor implements MongoParameterAccessor {
 	 */
 	public ConvertingParameterAccessor(MongoWriter<?> writer, MongoParameterAccessor delegate) {
 
-		Assert.notNull(writer);
-		Assert.notNull(delegate);
+		Assert.notNull(writer, "MongoWriter must not be null!");
+		Assert.notNull(delegate, "MongoParameterAccessor must not be null!");
 
 		this.writer = writer;
 		this.delegate = delegate;
 	}
 
 	/*
-	  * (non-Javadoc)
-	  *
-	  * @see java.lang.Iterable#iterator()
-	  */
+	 * (non-Javadoc)
+	 *
+	 * @see java.lang.Iterable#iterator()
+	 */
 	public PotentiallyConvertingIterator iterator() {
 		return new ConvertingIterator(delegate.iterator());
 	}
 
 	/*
-	  * (non-Javadoc)
-	  *
-	  * @see org.springframework.data.repository.query.ParameterAccessor#getPageable()
-	  */
+	 * (non-Javadoc)
+	 *
+	 * @see org.springframework.data.repository.query.ParameterAccessor#getPageable()
+	 */
 	public Pageable getPageable() {
 		return delegate.getPageable();
 	}
 
 	/*
-	  * (non-Javadoc)
-	  *
-	  * @see org.springframework.data.repository.query.ParameterAccessor#getSort()
-	  */
+	 * (non-Javadoc)
+	 *
+	 * @see org.springframework.data.repository.query.ParameterAccessor#getSort()
+	 */
 	public Sort getSort() {
 		return delegate.getSort();
 	}
 
-	/* 
+	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.repository.query.ParameterAccessor#getDynamicProjection()
 	 */
@@ -107,7 +108,7 @@ public class ConvertingParameterAccessor implements MongoParameterAccessor {
 		return getConvertedValue(delegate.getBindableValue(index), null);
 	}
 
-	/* 
+	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.mongodb.repository.query.MongoParameterAccessor#getDistanceRange()
 	 */
@@ -116,7 +117,7 @@ public class ConvertingParameterAccessor implements MongoParameterAccessor {
 		return delegate.getDistanceRange();
 	}
 
-	/* 
+	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.mongodb.repository.MongoParameterAccessor#getGeoNearLocation()
 	 */
@@ -143,7 +144,7 @@ public class ConvertingParameterAccessor implements MongoParameterAccessor {
 		return writer.convertToMongoType(value, typeInformation == null ? null : typeInformation.getActualType());
 	}
 
-	/* 
+	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.repository.query.ParameterAccessor#hasBindableNullValue()
 	 */
@@ -185,7 +186,7 @@ public class ConvertingParameterAccessor implements MongoParameterAccessor {
 			return delegate.next();
 		}
 
-		/* 
+		/*
 		 * (non-Javadoc)
 		 * @see org.springframework.data.mongodb.repository.ConvertingParameterAccessor.PotentiallConvertingIterator#nextConverted()
 		 */
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/query/MongoQueryCreator.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/query/MongoQueryCreator.java
index 694593ce5..0d40ed4d2 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/query/MongoQueryCreator.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/query/MongoQueryCreator.java
@@ -92,7 +92,7 @@ class MongoQueryCreator extends AbstractQueryCreator<Query, Criteria> {
 
 		super(tree, accessor);
 
-		Assert.notNull(context);
+		Assert.notNull(context, "MappingContext must not be null!");
 
 		this.accessor = accessor;
 		this.isGeoNearQuery = isGeoNearQuery;
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/support/IndexEnsuringQueryCreationListener.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/support/IndexEnsuringQueryCreationListener.java
index 4faa11e54..8259141e7 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/support/IndexEnsuringQueryCreationListener.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/support/IndexEnsuringQueryCreationListener.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2013 the original author or authors.
+ * Copyright 2011-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -57,7 +57,7 @@ class IndexEnsuringQueryCreationListener implements QueryCreationListener<PartTr
 	 */
 	public IndexEnsuringQueryCreationListener(IndexOperationsProvider indexOperationsProvider) {
 
-		Assert.notNull(indexOperationsProvider);
+		Assert.notNull(indexOperationsProvider, "IndexOperationsProvider must not be null!");
 		this.indexOperationsProvider = indexOperationsProvider;
 	}
 
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/support/MongoRepositoryFactory.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/support/MongoRepositoryFactory.java
index 85bb6a037..7adc158b7 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/support/MongoRepositoryFactory.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/support/MongoRepositoryFactory.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2015 the original author or authors.
+ * Copyright 2010-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,7 +21,6 @@ import java.io.Serializable;
 import java.lang.reflect.Method;
 
 import org.springframework.dao.InvalidDataAccessApiUsageException;
-import org.springframework.data.domain.Persistable;
 import org.springframework.data.mapping.context.MappingContext;
 import org.springframework.data.mapping.model.MappingException;
 import org.springframework.data.mongodb.core.MongoOperations;
@@ -56,6 +55,7 @@ import org.springframework.util.ClassUtils;
  * @author Oliver Gierke
  * @author Thomas Darimont
  * @author Christoph Strobl
+ * @author Mark Paluch
  */
 public class MongoRepositoryFactory extends RepositoryFactorySupport {
 
@@ -77,7 +77,7 @@ public class MongoRepositoryFactory extends RepositoryFactorySupport {
 	 */
 	public MongoRepositoryFactory(MongoOperations mongoOperations) {
 
-		Assert.notNull(mongoOperations);
+		Assert.notNull(mongoOperations, "MongoOperations must not be null!");
 
 		this.operations = mongoOperations;
 		this.mappingContext = mongoOperations.getConverter().getMappingContext();
@@ -121,7 +121,7 @@ public class MongoRepositoryFactory extends RepositoryFactorySupport {
 		return getTargetRepositoryViaReflection(information, entityInformation, operations);
 	}
 
-	/* 
+	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.repository.core.support.RepositoryFactorySupport#getQueryLookupStrategy(org.springframework.data.repository.query.QueryLookupStrategy.Key, org.springframework.data.repository.query.EvaluationContextProvider)
 	 */
@@ -173,7 +173,7 @@ public class MongoRepositoryFactory extends RepositoryFactorySupport {
 			this.mappingContext = mappingContext;
 		}
 
-		/* 
+		/*
 		 * (non-Javadoc)
 		 * @see org.springframework.data.repository.query.QueryLookupStrategy#resolveQuery(java.lang.reflect.Method, org.springframework.data.repository.core.RepositoryMetadata, org.springframework.data.projection.ProjectionFactory, org.springframework.data.repository.core.NamedQueries)
 		 */
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/support/QueryDslMongoRepository.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/support/QueryDslMongoRepository.java
index 70545bbbc..59d22ea81 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/support/QueryDslMongoRepository.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/support/QueryDslMongoRepository.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2016 the original author or authors.
+ * Copyright 2011-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -80,7 +80,8 @@ public class QueryDslMongoRepository<T, ID extends Serializable> extends SimpleM
 
 		super(entityInformation, mongoOperations);
 
-		Assert.notNull(resolver);
+		Assert.notNull(resolver, "EntityPathResolver must not be null!");
+
 		EntityPath<T> path = resolver.createPath(entityInformation.getJavaType());
 
 		this.builder = new PathBuilder<T>(path.getType(), path.getMetadata());
@@ -125,7 +126,7 @@ public class QueryDslMongoRepository<T, ID extends Serializable> extends SimpleM
 		return applySorting(createQueryFor(predicate), sort).fetchResults().getResults();
 	}
 
-	/* 
+	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.querydsl.QueryDslPredicateExecutor#findAll(com.mysema.query.types.OrderSpecifier[])
 	 */
@@ -188,7 +189,7 @@ public class QueryDslMongoRepository<T, ID extends Serializable> extends SimpleM
 		return createQueryFor(predicate).fetchCount();
 	}
 
-	/* 
+	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.querydsl.QueryDslPredicateExecutor#exists(com.mysema.query.types.Predicate)
 	 */
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/support/QuerydslRepositorySupport.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/support/QuerydslRepositorySupport.java
index bce77cd8b..bbfe8dd9b 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/support/QuerydslRepositorySupport.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/support/QuerydslRepositorySupport.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2015 the original author or authors.
+ * Copyright 2011-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -27,6 +27,7 @@ import com.querydsl.mongodb.AbstractMongodbQuery;
  * Base class to create repository implementations based on Querydsl.
  * 
  * @author Oliver Gierke
+ * @author Mark Paluch
  */
 public abstract class QuerydslRepositorySupport {
 
@@ -40,7 +41,7 @@ public abstract class QuerydslRepositorySupport {
 	 */
 	public QuerydslRepositorySupport(MongoOperations operations) {
 
-		Assert.notNull(operations);
+		Assert.notNull(operations, "MongoOperations must not be null!");
 
 		this.template = operations;
 		this.context = operations.getConverter().getMappingContext();
@@ -54,7 +55,9 @@ public abstract class QuerydslRepositorySupport {
 	 * @return
 	 */
 	protected <T> AbstractMongodbQuery<T, SpringDataMongodbQuery<T>> from(final EntityPath<T> path) {
-		Assert.notNull(path);
+
+		Assert.notNull(path, "EntityPath must not be null!");
+
 		MongoPersistentEntity<?> entity = context.getPersistentEntity(path.getType());
 		return from(path, entity.getCollection());
 	}
@@ -68,8 +71,8 @@ public abstract class QuerydslRepositorySupport {
 	 */
 	protected <T> AbstractMongodbQuery<T, SpringDataMongodbQuery<T>> from(final EntityPath<T> path, String collection) {
 
-		Assert.notNull(path);
-		Assert.hasText(collection);
+		Assert.notNull(path, "EntityPath must not be null!");
+		Assert.hasText(collection, "Collection name must not be null or empty!");
 
 		return new SpringDataMongodbQuery<T>(template, path.getType(), collection);
 	}
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/support/ReactiveMongoRepositoryFactory.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/support/ReactiveMongoRepositoryFactory.java
index 1447cc86a..89cb9e7e9 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/support/ReactiveMongoRepositoryFactory.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/support/ReactiveMongoRepositoryFactory.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 the original author or authors.
+ * Copyright 2016-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -65,7 +65,7 @@ public class ReactiveMongoRepositoryFactory extends ReactiveRepositoryFactorySup
 	 */
 	public ReactiveMongoRepositoryFactory(ReactiveMongoOperations mongoOperations) {
 
-		Assert.notNull(mongoOperations);
+		Assert.notNull(mongoOperations, "ReactiveMongoOperations must not be null!");
 
 		this.operations = mongoOperations;
 		this.mappingContext = mongoOperations.getConverter().getMappingContext();
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/support/SimpleMongoRepository.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/support/SimpleMongoRepository.java
index 83665535c..c6549dff6 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/support/SimpleMongoRepository.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/support/SimpleMongoRepository.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2016 the original author or authors.
+ * Copyright 2010-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -61,8 +61,8 @@ public class SimpleMongoRepository<T, ID extends Serializable> implements MongoR
 	 */
 	public SimpleMongoRepository(MongoEntityInformation<T, ID> metadata, MongoOperations mongoOperations) {
 
-		Assert.notNull(mongoOperations);
-		Assert.notNull(metadata);
+		Assert.notNull(metadata, "MongoEntityInformation must not be null!");
+		Assert.notNull(mongoOperations, "MongoOperations must not be null!");
 
 		this.entityInformation = metadata;
 		this.mongoOperations = mongoOperations;
@@ -197,7 +197,7 @@ public class SimpleMongoRepository<T, ID extends Serializable> implements MongoR
 		return findAll(new Query());
 	}
 
-	/* 
+	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.repository.CrudRepository#findAll(java.lang.Iterable)
 	 */
@@ -231,7 +231,7 @@ public class SimpleMongoRepository<T, ID extends Serializable> implements MongoR
 		return findAll(new Query().with(sort));
 	}
 
-	/* 
+	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.mongodb.repository.MongoRepository#insert(java.lang.Object)
 	 */
@@ -244,7 +244,7 @@ public class SimpleMongoRepository<T, ID extends Serializable> implements MongoR
 		return entity;
 	}
 
-	/* 
+	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.mongodb.repository.MongoRepository#insert(java.lang.Iterable)
 	 */
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/support/SimpleReactiveMongoRepository.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/support/SimpleReactiveMongoRepository.java
index 93ae0fb9c..7c8fb1a9d 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/support/SimpleReactiveMongoRepository.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/support/SimpleReactiveMongoRepository.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 the original author or authors.
+ * Copyright 2016-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -27,8 +27,6 @@ import java.util.Set;
 
 import org.reactivestreams.Publisher;
 import org.springframework.data.domain.Example;
-import org.springframework.data.domain.Page;
-import org.springframework.data.domain.Pageable;
 import org.springframework.data.domain.Sort;
 import org.springframework.data.mongodb.core.ReactiveMongoOperations;
 import org.springframework.data.mongodb.core.query.Criteria;
@@ -61,8 +59,8 @@ public class SimpleReactiveMongoRepository<T, ID extends Serializable> implement
 	public SimpleReactiveMongoRepository(MongoEntityInformation<T, ID> metadata,
 			ReactiveMongoOperations mongoOperations) {
 
-		Assert.notNull(mongoOperations);
-		Assert.notNull(metadata);
+		Assert.notNull(metadata, "MongoEntityInformation must not be null!");
+		Assert.notNull(mongoOperations, "ReactiveMongoOperations must not be null!");
 
 		this.entityInformation = metadata;
 		this.mongoOperations = mongoOperations;
diff --git a/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/monitor/MongoMonitorIntegrationTests.java b/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/monitor/MongoMonitorIntegrationTests.java
index 5d07d58ba..d9d6e66d6 100644
--- a/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/monitor/MongoMonitorIntegrationTests.java
+++ b/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/monitor/MongoMonitorIntegrationTests.java
@@ -25,8 +25,6 @@ import org.junit.runner.RunWith;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.test.context.ContextConfiguration;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
-import org.springframework.util.Assert;
-import org.springframework.util.StringUtils;
 
 import com.mongodb.Mongo;
 
@@ -35,6 +33,7 @@ import com.mongodb.Mongo;
  * 
  * @author Mark Pollack
  * @author Thomas Darimont
+ * @author Mark Paluch
  */
 @RunWith(SpringJUnit4ClassRunner.class)
 @ContextConfiguration("classpath:infrastructure.xml")
@@ -46,7 +45,6 @@ public class MongoMonitorIntegrationTests {
 	public void serverInfo() {
 		ServerInfo serverInfo = new ServerInfo(mongo);
 		serverInfo.getVersion();
-		Assert.isTrue(StringUtils.hasText("1."));
 	}
 
 	@Test // DATAMONGO-685
diff --git a/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/performance/PerformanceTests.java b/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/performance/PerformanceTests.java
index fad394af2..a0a448d6b 100644
--- a/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/performance/PerformanceTests.java
+++ b/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/performance/PerformanceTests.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2016 the original author or authors.
+ * Copyright 2012-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,7 +17,6 @@ package org.springframework.data.mongodb.performance;
 
 import static org.springframework.data.mongodb.core.query.Criteria.*;
 import static org.springframework.data.mongodb.core.query.Query.*;
-import static org.springframework.util.Assert.*;
 
 import java.text.DecimalFormat;
 import java.util.ArrayList;
@@ -48,6 +47,7 @@ import org.springframework.data.mongodb.core.mapping.MongoMappingContext;
 import org.springframework.data.mongodb.core.query.Query;
 import org.springframework.data.mongodb.repository.MongoRepository;
 import org.springframework.data.mongodb.repository.support.MongoRepositoryFactoryBean;
+import org.springframework.util.Assert;
 import org.springframework.util.StopWatch;
 import org.springframework.util.StringUtils;
 
@@ -67,6 +67,7 @@ import com.mongodb.WriteConcern;
  * 
  * @author Oliver Gierke
  * @author Christoph Strobl
+ * @author Mark Paluch
  */
 public class PerformanceTests {
 
@@ -623,7 +624,7 @@ public class PerformanceTests {
 
 	private static <T> List<T> pickRandomNumerOfItemsFrom(List<T> source) {
 
-		isTrue(!source.isEmpty());
+		Assert.isTrue(!source.isEmpty(), "Source must not be empty!");
 
 		Random random = new Random();
 		int numberOfItems = random.nextInt(source.size());
@@ -837,7 +838,7 @@ public class PerformanceTests {
 					String.format(" %s%%", DEVIATION_FORMAT.format(getMediaDeviationFrom(referenceMedian)))) + '\n';
 		}
 
-		/* 
+		/*
 		 * (non-Javadoc)
 		 * @see java.lang.Object#toString()
 		 */
@@ -896,7 +897,7 @@ public class PerformanceTests {
 			return builder.toString();
 		}
 
-		/* 
+		/*
 		 * (non-Javadoc)
 		 * @see java.lang.Object#toString()
 		 */
diff --git a/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/performance/ReactivePerformanceTests.java b/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/performance/ReactivePerformanceTests.java
index 4d2698d90..b5d84ffeb 100644
--- a/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/performance/ReactivePerformanceTests.java
+++ b/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/performance/ReactivePerformanceTests.java
@@ -17,8 +17,8 @@ package org.springframework.data.mongodb.performance;
 
 import static org.springframework.data.mongodb.core.query.Criteria.*;
 import static org.springframework.data.mongodb.core.query.Query.*;
-import static org.springframework.util.Assert.*;
 
+import org.springframework.util.Assert;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 
@@ -670,7 +670,7 @@ public class ReactivePerformanceTests {
 
 	private static <T> List<T> pickRandomNumerOfItemsFrom(List<T> source) {
 
-		isTrue(!source.isEmpty());
+		Assert.isTrue(!source.isEmpty(), "Source must not be empty!");
 
 		Random random = new Random();
 		int numberOfItems = random.nextInt(source.size());
@@ -884,7 +884,7 @@ public class ReactivePerformanceTests {
 					String.format(" %s%%", DEVIATION_FORMAT.format(getMediaDeviationFrom(referenceMedian)))) + '\n';
 		}
 
-		/* 
+		/*
 		 * (non-Javadoc)
 		 * @see java.lang.Object#toString()
 		 */
@@ -943,7 +943,7 @@ public class ReactivePerformanceTests {
 			return builder.toString();
 		}
 
-		/* 
+		/*
 		 * (non-Javadoc)
 		 * @see java.lang.Object#toString()
 		 */