diff --git a/src/main/java/org/springframework/hateoas/PagedResources.java b/src/main/java/org/springframework/hateoas/PagedResources.java
index 972609e2..8cf0c126 100644
--- a/src/main/java/org/springframework/hateoas/PagedResources.java
+++ b/src/main/java/org/springframework/hateoas/PagedResources.java
@@ -89,7 +89,7 @@ public class PagedResources<T> extends Resources<T> {
 	@SuppressWarnings("unchecked")
 	public static <T extends Resource<S>, S> PagedResources<T> wrap(Iterable<S> content, PageMetadata metadata) {
 
-		Assert.notNull(content);
+		Assert.notNull(content, "Content must not be null!");
 		ArrayList<T> resources = new ArrayList<T>();
 
 		for (S element : content) {
diff --git a/src/main/java/org/springframework/hateoas/Resources.java b/src/main/java/org/springframework/hateoas/Resources.java
index 04f4142a..5ca199b1 100644
--- a/src/main/java/org/springframework/hateoas/Resources.java
+++ b/src/main/java/org/springframework/hateoas/Resources.java
@@ -64,7 +64,7 @@ public class Resources<T> extends ResourceSupport implements Iterable<T> {
 	 */
 	public Resources(Iterable<T> content, Iterable<Link> links) {
 
-		Assert.notNull(content);
+		Assert.notNull(content, "Content must not be null!");
 
 		this.content = new ArrayList<T>();
 
@@ -83,7 +83,7 @@ public class Resources<T> extends ResourceSupport implements Iterable<T> {
 	@SuppressWarnings("unchecked")
 	public static <T extends Resource<S>, S> Resources<T> wrap(Iterable<S> content) {
 
-		Assert.notNull(content);
+		Assert.notNull(content, "Content must not be null!");
 		ArrayList<T> resources = new ArrayList<T>();
 
 		for (S element : content) {
diff --git a/src/main/java/org/springframework/hateoas/core/AbstractEntityLinks.java b/src/main/java/org/springframework/hateoas/core/AbstractEntityLinks.java
index 55a787fd..3aebe2f4 100644
--- a/src/main/java/org/springframework/hateoas/core/AbstractEntityLinks.java
+++ b/src/main/java/org/springframework/hateoas/core/AbstractEntityLinks.java
@@ -35,7 +35,7 @@ public abstract class AbstractEntityLinks implements EntityLinks {
 	 */
 	@Override
 	public Link linkToSingleResource(Identifiable<?> entity) {
-		Assert.notNull(entity);
+		Assert.notNull(entity, "Entity must not be null!");
 		return linkToSingleResource(entity.getClass(), entity.getId());
 	}
 
@@ -54,7 +54,7 @@ public abstract class AbstractEntityLinks implements EntityLinks {
 	 */
 	@Override
 	public LinkBuilder linkForSingleResource(Identifiable<?> entity) {
-		Assert.notNull(entity);
+		Assert.notNull(entity, "Entity must not be null!");
 		return linkForSingleResource(entity.getClass(), entity.getId());
 	}
 }
diff --git a/src/main/java/org/springframework/hateoas/core/AnnotationAttribute.java b/src/main/java/org/springframework/hateoas/core/AnnotationAttribute.java
index 7c9dde0b..d67ecac1 100644
--- a/src/main/java/org/springframework/hateoas/core/AnnotationAttribute.java
+++ b/src/main/java/org/springframework/hateoas/core/AnnotationAttribute.java
@@ -49,7 +49,7 @@ public class AnnotationAttribute {
 	 */
 	public AnnotationAttribute(Class<? extends Annotation> annotationType, String attributeName) {
 
-		Assert.notNull(annotationType);
+		Assert.notNull(annotationType, "AnnotationType must not be null!");
 
 		this.annotationType = annotationType;
 		this.attributeName = attributeName;
diff --git a/src/main/java/org/springframework/hateoas/core/AnnotationMappingDiscoverer.java b/src/main/java/org/springframework/hateoas/core/AnnotationMappingDiscoverer.java
index 2cc062d1..a40cb44e 100644
--- a/src/main/java/org/springframework/hateoas/core/AnnotationMappingDiscoverer.java
+++ b/src/main/java/org/springframework/hateoas/core/AnnotationMappingDiscoverer.java
@@ -55,7 +55,7 @@ public class AnnotationMappingDiscoverer implements MappingDiscoverer {
 	 */
 	public AnnotationMappingDiscoverer(Class<? extends Annotation> annotation, String mappingAttributeName) {
 
-		Assert.notNull(annotation);
+		Assert.notNull(annotation, "Annotation must not be null!");
 
 		this.annotationType = annotation;
 		this.mappingAttributeName = mappingAttributeName;
diff --git a/src/main/java/org/springframework/hateoas/core/ControllerEntityLinks.java b/src/main/java/org/springframework/hateoas/core/ControllerEntityLinks.java
index 42d9771f..d1966315 100644
--- a/src/main/java/org/springframework/hateoas/core/ControllerEntityLinks.java
+++ b/src/main/java/org/springframework/hateoas/core/ControllerEntityLinks.java
@@ -65,8 +65,8 @@ public class ControllerEntityLinks extends AbstractEntityLinks {
 	public ControllerEntityLinks(Iterable<? extends Class<?>> controllerTypes,
 			LinkBuilderFactory<? extends LinkBuilder> linkBuilderFactory) {
 
-		Assert.notNull(controllerTypes);
-		Assert.notNull(linkBuilderFactory);
+		Assert.notNull(controllerTypes, "ControllerTypes must not be null!");
+		Assert.notNull(linkBuilderFactory, "LinkBuilderFactory must not be null!");
 
 		this.linkBuilderFactory = linkBuilderFactory;
 		this.entityToController = new HashMap<Class<?>, Class<?>>();
@@ -105,7 +105,7 @@ public class ControllerEntityLinks extends AbstractEntityLinks {
 	@Override
 	public LinkBuilder linkFor(Class<?> entity, Object... parameters) {
 
-		Assert.notNull(entity);
+		Assert.notNull(entity, "Entity must not be null!");
 
 		Class<?> controllerType = entityToController.get(entity);
 
diff --git a/src/main/java/org/springframework/hateoas/core/ControllerEntityLinksFactoryBean.java b/src/main/java/org/springframework/hateoas/core/ControllerEntityLinksFactoryBean.java
index 6f5cf671..570cd31c 100644
--- a/src/main/java/org/springframework/hateoas/core/ControllerEntityLinksFactoryBean.java
+++ b/src/main/java/org/springframework/hateoas/core/ControllerEntityLinksFactoryBean.java
@@ -49,7 +49,7 @@ public class ControllerEntityLinksFactoryBean extends AbstractFactoryBean<Contro
 	 * @param annotation must not be {@literal null}.
 	 */
 	public void setAnnotation(Class<? extends Annotation> annotation) {
-		Assert.notNull(annotation);
+		Assert.notNull(annotation, "Annotation must not be null!");
 		this.annotation = annotation;
 	}
 
diff --git a/src/main/java/org/springframework/hateoas/core/MethodParameters.java b/src/main/java/org/springframework/hateoas/core/MethodParameters.java
index 2bd55ad8..4dd551e9 100644
--- a/src/main/java/org/springframework/hateoas/core/MethodParameters.java
+++ b/src/main/java/org/springframework/hateoas/core/MethodParameters.java
@@ -57,7 +57,7 @@ public class MethodParameters {
 	 */
 	public MethodParameters(Method method, AnnotationAttribute namingAnnotation) {
 
-		Assert.notNull(method);
+		Assert.notNull(method, "Method must not be null!");
 		this.parameters = new ArrayList<MethodParameter>();
 
 		for (int i = 0; i < method.getParameterTypes().length; i++) {
@@ -131,7 +131,7 @@ public class MethodParameters {
 			return cached;
 		}
 
-		Assert.notNull(annotation);
+		Assert.notNull(annotation, "Annotation must not be null!");
 		List<MethodParameter> result = new ArrayList<MethodParameter>();
 
 		for (MethodParameter parameter : getParameters()) {
diff --git a/src/main/java/org/springframework/hateoas/mvc/ControllerRelProvider.java b/src/main/java/org/springframework/hateoas/mvc/ControllerRelProvider.java
index 69aa9c03..1cdd9fc9 100644
--- a/src/main/java/org/springframework/hateoas/mvc/ControllerRelProvider.java
+++ b/src/main/java/org/springframework/hateoas/mvc/ControllerRelProvider.java
@@ -32,10 +32,10 @@ public class ControllerRelProvider implements RelProvider {
 
 	public ControllerRelProvider(Class<?> controller, PluginRegistry<RelProvider, Class<?>> providers) {
 
-		Assert.notNull(controller);
+		Assert.notNull(controller, "Controller must not be null!");
 
 		ExposesResourceFor annotation = AnnotationUtils.findAnnotation(controller, ExposesResourceFor.class);
-		Assert.notNull(annotation);
+		Assert.notNull(annotation, "Controller must be annotated with ExposesResourceFor!");
 
 		this.controllerType = controller;
 		this.entityType = annotation.value();
diff --git a/src/main/java/org/springframework/hateoas/mvc/IdentifiableResourceAssemblerSupport.java b/src/main/java/org/springframework/hateoas/mvc/IdentifiableResourceAssemblerSupport.java
index 31fc0938..bae0cd22 100644
--- a/src/main/java/org/springframework/hateoas/mvc/IdentifiableResourceAssemblerSupport.java
+++ b/src/main/java/org/springframework/hateoas/mvc/IdentifiableResourceAssemblerSupport.java
@@ -66,8 +66,8 @@ public abstract class IdentifiableResourceAssemblerSupport<T extends Identifiabl
 	@Override
 	protected D createResourceWithId(Object id, T entity, Object... parameters) {
 
-		Assert.notNull(entity);
-		Assert.notNull(id);
+		Assert.notNull(entity, "Entity must not be null!");
+		Assert.notNull(id, "Id must not be null!");
 
 		D instance = instantiateResource(entity);
 		instance.add(linkTo(controllerClass, unwrapIdentifyables(parameters)).slash(id).withSelfRel());
diff --git a/src/main/java/org/springframework/hateoas/mvc/ResourceAssemblerSupport.java b/src/main/java/org/springframework/hateoas/mvc/ResourceAssemblerSupport.java
index 13a3648c..2d51ab2c 100755
--- a/src/main/java/org/springframework/hateoas/mvc/ResourceAssemblerSupport.java
+++ b/src/main/java/org/springframework/hateoas/mvc/ResourceAssemblerSupport.java
@@ -44,8 +44,8 @@ public abstract class ResourceAssemblerSupport<T, D extends ResourceSupport> imp
 	 */
 	public ResourceAssemblerSupport(Class<?> controllerClass, Class<D> resourceType) {
 
-		Assert.notNull(controllerClass);
-		Assert.notNull(resourceType);
+		Assert.notNull(controllerClass, "ControllerClass must not be null!");
+		Assert.notNull(resourceType, "ResourceType must not be null!");
 
 		this.controllerClass = controllerClass;
 		this.resourceType = resourceType;
@@ -60,7 +60,7 @@ public abstract class ResourceAssemblerSupport<T, D extends ResourceSupport> imp
 	 */
 	public List<D> toResources(Iterable<? extends T> entities) {
 
-		Assert.notNull(entities);
+		Assert.notNull(entities, "Entities must not be null!");
 		List<D> result = new ArrayList<D>();
 
 		for (T entity : entities) {
@@ -83,8 +83,8 @@ public abstract class ResourceAssemblerSupport<T, D extends ResourceSupport> imp
 
 	protected D createResourceWithId(Object id, T entity, Object... parameters) {
 
-		Assert.notNull(entity);
-		Assert.notNull(id);
+		Assert.notNull(entity, "Entity must not be null!");
+		Assert.notNull(id, "Id must not be null!");
 
 		D instance = instantiateResource(entity);
 		instance.add(linkTo(controllerClass, parameters).slash(id).withSelfRel());
diff --git a/src/main/java/org/springframework/hateoas/mvc/ResourceProcessorInvoker.java b/src/main/java/org/springframework/hateoas/mvc/ResourceProcessorInvoker.java
index 8b2e778b..e3003e3f 100644
--- a/src/main/java/org/springframework/hateoas/mvc/ResourceProcessorInvoker.java
+++ b/src/main/java/org/springframework/hateoas/mvc/ResourceProcessorInvoker.java
@@ -199,7 +199,7 @@ public class ResourceProcessorInvoker {
 		 */
 		public DefaultProcessorWrapper(ResourceProcessor<?> processor) {
 
-			Assert.notNull(processor);
+			Assert.notNull(processor, "Processor must not be null!");
 
 			this.processor = processor;
 			this.targetType = ResolvableType.forClass(ResourceProcessor.class, processor.getClass()).getGeneric(0);
diff --git a/src/main/java/org/springframework/hateoas/mvc/TypeReferences.java b/src/main/java/org/springframework/hateoas/mvc/TypeReferences.java
index b352b10d..9bd258e7 100644
--- a/src/main/java/org/springframework/hateoas/mvc/TypeReferences.java
+++ b/src/main/java/org/springframework/hateoas/mvc/TypeReferences.java
@@ -84,7 +84,7 @@ public class TypeReferences {
 			Type type = parameterizedTypeReferenceSubclass.getGenericSuperclass();
 			Assert.isInstanceOf(ParameterizedType.class, type);
 			ParameterizedType parameterizedType = (ParameterizedType) type;
-			Assert.isTrue(parameterizedType.getActualTypeArguments().length == 1);
+			Assert.isTrue(parameterizedType.getActualTypeArguments().length == 1, String.format("Type must have exactly one gerneric type argument but has %s.", parameterizedType.getActualTypeArguments().length));
 
 			Class<?> resourceType = GenericTypeResolver.resolveType(parameterizedType.getActualTypeArguments()[0],
 					new HashMap<TypeVariable, Type>());