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 3aae75689..fa4ac4946 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 2011-2014 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.
@@ -361,7 +361,9 @@ 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 f82371c74..ac4c24998 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.
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 b7e0d672c..7351d0711 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
@@ -211,7 +211,7 @@ 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();
@@ -423,7 +423,7 @@ 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!");
 
 		DBObject queryObject = queryMapper.getMappedObject(query.getQueryObject(), null);
 		DBObject sortObject = query.getSortObject();
@@ -439,7 +439,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 
 	public <T> T execute(DbCallback<T> action) {
 
-		Assert.notNull(action);
+		Assert.notNull(action, "DbCallbackmust not be null!");
 
 		try {
 			DB db = this.getDb();
@@ -455,7 +455,7 @@ 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 {
 			DBCollection collection = getAndPrepareCollection(getDb(), collectionName);
@@ -733,7 +733,8 @@ 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));
 	}
 
@@ -747,7 +748,8 @@ 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 DBObject dbObject = query == null ? null
 				: queryMapper.getMappedObject(query.getQueryObject(),
 						entityClass == null ? null : mappingContext.getPersistentEntity(entityClass));
@@ -918,7 +920,7 @@ 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<DBObject> dbObjectList = new ArrayList<DBObject>();
 		for (T o : batchToSave) {
@@ -947,14 +949,14 @@ 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());
 
@@ -1200,7 +1202,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 
 	public WriteResult remove(Object object, String collection) {
 
-		Assert.hasText(collection);
+		Assert.hasText(collection, "Collection name must not be null or empty!");
 
 		if (object == null) {
 			return null;
@@ -2281,8 +2283,9 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 
 		public ReadDbObjectCallback(EntityReader<? super T, DBObject> 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;
@@ -2404,7 +2407,9 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 		 * @param delegate must not be {@literal null}.
 		 */
 		public GeoNearResultDbObjectCallback(DbObjectCallback<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 2fbf96c4c..822335887 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 2013-2014 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 com.mongodb.DBObject;
  * @author Tobias Trelle
  * @author Oliver Gierke
  * @author Thomas Darimont
+ * @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, DBObject 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 307554186..859b42236 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,
@@ -310,7 +310,7 @@ 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)
 	 */
@@ -478,7 +478,7 @@ 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) {
@@ -825,7 +825,7 @@ 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;
@@ -1053,7 +1053,7 @@ 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
@@ -1114,22 +1114,22 @@ 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(DBObject source, SpELExpressionEvaluator evaluator, ObjectPath path) {
 
-			Assert.notNull(source);
-			Assert.notNull(evaluator);
+			Assert.notNull(source, "DBObject must not be null!");
+			Assert.notNull(evaluator, "SpELExpressionEvaluator must not be null!");
 
 			this.source = new DBObjectAccessor(source);
 			this.evaluator = evaluator;
 			this.path = path;
 		}
 
-		/* 
+		/*
 		 * (non-Javadoc)
 		 * @see org.springframework.data.convert.PropertyValueProvider#getPropertyValue(org.springframework.data.mapping.PersistentProperty)
 		 */
@@ -1172,7 +1172,7 @@ 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 d80423446..cabce8eed 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.
@@ -82,7 +82,7 @@ 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 83bf35436..0e433aa21 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.
@@ -44,8 +44,13 @@ 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;
@@ -58,17 +63,21 @@ public final class IndexField {
 	 * 
 	 * @deprecated use {@link #create(String, Direction)}.
 	 * @param key must not be {@literal null} or emtpy.
-	 * @param direction must not be {@literal null}.
+	 * @param order must not be {@literal null}.
 	 * @return
 	 */
 	@Deprecated
 	public static IndexField create(String key, Order order) {
-		Assert.notNull(order);
+		
+		Assert.notNull(order, "Order must not be null!");
+
 		return new IndexField(key, order.toDirection(), Type.DEFAULT);
 	}
 
 	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);
 	}
 
@@ -128,7 +137,7 @@ 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
@@ -158,7 +167,7 @@ public final class IndexField {
 				&& this.type == that.type;
 	}
 
-	/* 
+	/*
 	 * (non-Javadoc)
 	 * @see java.lang.Object#hashCode()
 	 */
@@ -173,7 +182,7 @@ 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 f4d4d6700..4d9e5a182 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.
@@ -32,6 +32,7 @@ import com.mongodb.DBObject;
  * @author Mark Pollack
  * @author Oliver Gierke
  * @author Christoph Strobl
+ * @author Mark Paluch
  */
 public class IndexInfo {
 
@@ -147,7 +148,8 @@ 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 41018a8c8..7febac08a 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 2011-2015 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.
@@ -79,9 +79,9 @@ public class MongoPersistentEntityIndexCreator implements ApplicationListener<Ma
 	public MongoPersistentEntityIndexCreator(MongoMappingContext mappingContext, MongoDbFactory mongoDbFactory,
 			IndexResolver indexResolver) {
 
-		Assert.notNull(mongoDbFactory);
-		Assert.notNull(mappingContext);
-		Assert.notNull(indexResolver);
+		Assert.notNull(mappingContext, "MongoMappingContext must not be null!");
+		Assert.notNull(mongoDbFactory, "MongoDbFactory must not be null!");
+		Assert.notNull(indexResolver, "IndexResolver must not be null!");
 
 		this.mongoDbFactory = mongoDbFactory;
 		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 a3dc65ee8..9b090b77f 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 - 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.
  * 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,
@@ -27,6 +27,7 @@ import com.mongodb.DBObject;
  * 
  * @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> {
@@ -40,10 +41,12 @@ public class GroupByResults<T> implements Iterable<T> {
 
 	public GroupByResults(List<T> mappedResults, DBObject 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 4d7c1407e..282791752 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 2011-2015 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.
  * 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, DBObject 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 0836cdae9..2821ee321 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.DBObject;
  * @author Oliver Gierke
  * @author Thomas Darimont
  * @author Christoph Strobl
+ * @author Mark Paluch
  */
 public class Criteria implements CriteriaDefinition {
 
@@ -387,7 +388,7 @@ 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);
@@ -398,7 +399,9 @@ 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));
 	}
 
@@ -412,7 +415,9 @@ public class Criteria implements CriteriaDefinition {
 	 * @return
 	 */
 	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;
 	}
@@ -426,7 +431,8 @@ public class Criteria implements CriteriaDefinition {
 	 */
 	public Criteria within(Shape shape) {
 
-		Assert.notNull(shape);
+		Assert.notNull(shape, "Shape must not be null!");
+
 		criteria.put("$geoWithin", new GeoCommand(shape));
 		return this;
 	}
@@ -439,7 +445,9 @@ public class Criteria implements CriteriaDefinition {
 	 * @return
 	 */
 	public Criteria near(Point point) {
-		Assert.notNull(point);
+
+		Assert.notNull(point, "Point must not be null!");
+
 		criteria.put("$near", point);
 		return this;
 	}
@@ -453,7 +461,9 @@ public class Criteria implements CriteriaDefinition {
 	 * @return
 	 */
 	public Criteria nearSphere(Point point) {
-		Assert.notNull(point);
+
+		Assert.notNull(point, "Point must not be null!");
+
 		criteria.put("$nearSphere", point);
 		return this;
 	}
@@ -707,7 +717,7 @@ public class Criteria implements CriteriaDefinition {
 		return false;
 	}
 
-	/* 
+	/*
 	 * (non-Javadoc)
 	 * @see java.lang.Object#equals(java.lang.Object)
 	 */
@@ -770,7 +780,7 @@ 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 b847d192e..22a571e90 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 2011-2015 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.
  * 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,
@@ -49,11 +49,11 @@ 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;
@@ -108,7 +108,6 @@ public final class NearQuery {
 	 * @return
 	 */
 	public static NearQuery near(Point point, Metric metric) {
-		Assert.notNull(point);
 		return new NearQuery(point, metric);
 	}
 
@@ -185,7 +184,8 @@ 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));
 	}
 
@@ -198,7 +198,7 @@ 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);
@@ -241,7 +241,8 @@ 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));
 	}
 
@@ -255,7 +256,7 @@ 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 b323b9cf3..763bbaa33 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 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 +29,8 @@ import org.springframework.util.Assert;
  * A value object for nodes in an expression. Allows iterating ove potentially available child {@link ExpressionNode}s.
  * 
  * @author Oliver Gierke
+ * @author Christoph Strobl
+ * @author Mark Paluch
  */
 public class ExpressionNode implements Iterable<ExpressionNode> {
 
@@ -157,7 +159,7 @@ 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);
 	}
 
@@ -183,7 +185,7 @@ 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 e523e8855..602cc7b5b 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.
@@ -46,6 +46,7 @@ import com.mongodb.gridfs.GridFSInputFile;
  * @author Thomas Darimont
  * @author Martin Baumgartner
  * @author Christoph Strobl
+ * @author Mark Paluch
  */
 public class GridFsTemplate implements GridFsOperations, ResourcePatternResolver {
 
@@ -73,8 +74,8 @@ 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;
@@ -156,7 +157,7 @@ public class GridFsTemplate implements GridFsOperations, ResourcePatternResolver
 	 */
 	public GridFSFile store(InputStream content, String filename, String contentType, DBObject metadata) {
 
-		Assert.notNull(content);
+		Assert.notNull(content, "InputStream must not be null!");
 
 		GridFSInputFile file = getGridFs().createFile(content);
 
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 c2820727d..77f6088f2 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 4ae998db9..2b6ddec1b 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.
@@ -53,7 +53,7 @@ class IndexEnsuringQueryCreationListener implements QueryCreationListener<PartTr
 	 */
 	public IndexEnsuringQueryCreationListener(MongoOperations operations) {
 
-		Assert.notNull(operations);
+		Assert.notNull(operations, "MongoOperations must not be null!");
 		this.operations = operations;
 	}
 
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 93224627e..e39ebbeda 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.
@@ -51,6 +51,7 @@ import org.springframework.util.ClassUtils;
  * @author Oliver Gierke
  * @author Thomas Darimont
  * @author Christoph Strobl
+ * @author Mark Paluch
  */
 public class MongoRepositoryFactory extends RepositoryFactorySupport {
 
@@ -66,7 +67,7 @@ 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();
@@ -97,7 +98,7 @@ 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)
 	 */
@@ -149,7 +150,7 @@ 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 9f759617c..cb653c3db 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 2011-2015 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.
@@ -78,7 +78,8 @@ 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());
@@ -122,7 +123,7 @@ 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[])
 	 */
@@ -177,7 +178,7 @@ 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/SimpleMongoRepository.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/support/SimpleMongoRepository.java
index 21af693ba..5d84a3a09 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.
@@ -59,8 +59,8 @@ 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;
@@ -195,7 +195,7 @@ 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)
 	 */
@@ -229,7 +229,7 @@ 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)
 	 */
@@ -242,7 +242,7 @@ 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/test/java/org/springframework/data/mongodb/monitor/MongoMonitorIntegrationTests.java b/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/monitor/MongoMonitorIntegrationTests.java
index da9290058..ca0f30fef 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
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2013 the original author or authors.
+ * Copyright 2002-2013 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.
@@ -15,63 +15,61 @@
  */
 package org.springframework.data.mongodb.monitor;
 
-import static org.hamcrest.Matchers.*;
-import static org.junit.Assert.*;
-
-import java.net.UnknownHostException;
-
+import static org.hamcrest.Matchers.*;
+import static org.junit.Assert.*;
+
+import java.net.UnknownHostException;
+
 import org.junit.Test;
 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;
-
+import com.mongodb.Mongo;
+
 /**
  * This test class assumes that you are already running the MongoDB server.
  * 
  * @author Mark Pollack
- * @author Thomas Darimont
+ * @author Thomas Darimont
+ * @author Mark Paluch
  */
 @RunWith(SpringJUnit4ClassRunner.class)
-@ContextConfiguration("classpath:infrastructure.xml")
+@ContextConfiguration("classpath:infrastructure.xml")
 public class MongoMonitorIntegrationTests {
 
-	@Autowired Mongo mongo;
+	@Autowired Mongo mongo;
 
 	@Test
 	public void serverInfo() {
 		ServerInfo serverInfo = new ServerInfo(mongo);
 		serverInfo.getVersion();
-		Assert.isTrue(StringUtils.hasText("1."));
 	}
 
-	/**
-	 * @throws UnknownHostException
-	 * @see DATAMONGO-685
-	 */
-	@Test
-	public void getHostNameShouldReturnServerNameReportedByMongo() throws UnknownHostException {
-
-		ServerInfo serverInfo = new ServerInfo(mongo);
-
-		String hostName = null;
-		try {
-			hostName = serverInfo.getHostName();
-		} catch (UnknownHostException e) {
-			throw e;
-		}
-
-		assertThat(hostName, is(notNullValue()));
-		assertThat(hostName, is("127.0.0.1"));
-	}
-
+	/**
+	 * @throws UnknownHostException
+	 * @see DATAMONGO-685
+	 */
+	@Test
+	public void getHostNameShouldReturnServerNameReportedByMongo() throws UnknownHostException {
+
+		ServerInfo serverInfo = new ServerInfo(mongo);
+
+		String hostName = null;
+		try {
+			hostName = serverInfo.getHostName();
+		} catch (UnknownHostException e) {
+			throw e;
+		}
+
+		assertThat(hostName, is(notNullValue()));
+		assertThat(hostName, is("127.0.0.1"));
+	}
+
 	@Test
 	public void operationCounters() {
 		OperationCounters operationCounters = new OperationCounters(mongo);
 		operationCounters.getInsertCount();
 	}
-}
+}
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 915572121..0bd21a81a 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;
@@ -47,6 +46,7 @@ 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;
 
@@ -66,6 +66,7 @@ import com.mongodb.WriteConcern;
  * 
  * @author Oliver Gierke
  * @author Christoph Strobl
+ * @author Mark Paluch
  */
 public class PerformanceTests {
 
@@ -622,7 +623,7 @@ 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());
@@ -836,7 +837,7 @@ public class PerformanceTests {
 					String.format(" %s%%", DEVIATION_FORMAT.format(getMediaDeviationFrom(referenceMedian)))) + '\n';
 		}
 
-		/* 
+		/*
 		 * (non-Javadoc)
 		 * @see java.lang.Object#toString()
 		 */
@@ -895,7 +896,7 @@ public class PerformanceTests {
 			return builder.toString();
 		}
 
-		/* 
+		/*
 		 * (non-Javadoc)
 		 * @see java.lang.Object#toString()
 		 */