diff --git a/src/main/java/io/wcm/handler/media/Media.java b/src/main/java/io/wcm/handler/media/Media.java
index 7fe640a5..8980e079 100644
--- a/src/main/java/io/wcm/handler/media/Media.java
+++ b/src/main/java/io/wcm/handler/media/Media.java
@@ -97,7 +97,7 @@ public void setMediaRequest(@NotNull MediaRequest mediaRequest) {
    * @return Html element
    */
   @JsonIgnore
-  public HtmlElement<?> getElement() {
+  public @Nullable HtmlElement<?> getElement() {
     if (this.element == null && this.elementBuilder != null) {
       this.element = this.elementBuilder.apply(this);
       this.elementBuilder = null;
@@ -109,7 +109,7 @@ public HtmlElement<?> getElement() {
    * @return Media HTML element serialized to string. Returns null if media element is null.
    */
   @JsonIgnore
-  public String getMarkup() {
+  public @Nullable String getMarkup() {
     HtmlElement<?> el = getElement();
     if (markup == null && el != null) {
       if (el instanceof Span) {
@@ -130,7 +130,7 @@ public String getMarkup() {
   /**
    * @param value Function that builds the HTML element representation on demand
    */
-  public void setElementBuilder(Function<Media, HtmlElement<?>> value) {
+  public void setElementBuilder(@NotNull Function<Media, HtmlElement<?>> value) {
     this.elementBuilder = value;
     this.markup = null;
   }
@@ -138,14 +138,14 @@ public void setElementBuilder(Function<Media, HtmlElement<?>> value) {
   /**
    * @return Media URL
    */
-  public String getUrl() {
+  public @Nullable String getUrl() {
     return this.url;
   }
 
   /**
    * @param value Media URL
    */
-  public void setUrl(String value) {
+  public void setUrl(@Nullable String value) {
     this.url = value;
   }
 
@@ -153,7 +153,7 @@ public void setUrl(String value) {
    * Get media item info that was resolved during media handler processing
    * @return Media item
    */
-  public Asset getAsset() {
+  public @Nullable Asset getAsset() {
     return this.asset;
   }
 
@@ -161,7 +161,7 @@ public Asset getAsset() {
    * Set media item that was resolved during media handler processing
    * @param asset Media item
    */
-  public void setAsset(Asset asset) {
+  public void setAsset(@Nullable Asset asset) {
     this.asset = asset;
   }
 
@@ -170,7 +170,7 @@ public void setAsset(Asset asset) {
    * @return Rendition
    */
   @JsonIgnore
-  public Rendition getRendition() {
+  public @Nullable Rendition getRendition() {
     if (this.renditions == null || this.renditions.isEmpty()) {
       return null;
     }
@@ -181,7 +181,7 @@ public Rendition getRendition() {
    * Get all renditions that were resolved during media handler processing
    * @return Renditions
    */
-  public Collection<Rendition> getRenditions() {
+  public @NotNull Collection<Rendition> getRenditions() {
     if (this.renditions == null) {
       return Collections.emptyList();
     }
@@ -194,7 +194,7 @@ public Collection<Rendition> getRenditions() {
    * Set all renditions that was resolved during media handler processing
    * @param renditions Renditions
    */
-  public void setRenditions(Collection<Rendition> renditions) {
+  public void setRenditions(@Nullable Collection<Rendition> renditions) {
     this.renditions = renditions;
   }
 
@@ -254,14 +254,14 @@ public boolean isValid() {
    * @return Reason why the requested media could not be resolved and is invalid
    */
   @JsonIgnore
-  public MediaInvalidReason getMediaInvalidReason() {
+  public @Nullable MediaInvalidReason getMediaInvalidReason() {
     return this.mediaInvalidReason;
   }
 
   /**
    * @param mediaInvalidReason Reason why the requested media could not be resolved and is invalid
    */
-  public void setMediaInvalidReason(MediaInvalidReason mediaInvalidReason) {
+  public void setMediaInvalidReason(@Nullable MediaInvalidReason mediaInvalidReason) {
     this.mediaInvalidReason = mediaInvalidReason;
   }
 
@@ -269,7 +269,7 @@ public void setMediaInvalidReason(MediaInvalidReason mediaInvalidReason) {
    * @return Custom message when {@link #getMediaInvalidReason()} is set to {@link MediaInvalidReason#CUSTOM}.
    *         Message is interpreted as i18n key.
    */
-  public String getMediaInvalidReasonCustomMessage() {
+  public @Nullable String getMediaInvalidReasonCustomMessage() {
     return this.mediaInvalidReasonCustomMessage;
   }
 
@@ -277,7 +277,7 @@ public String getMediaInvalidReasonCustomMessage() {
    * @param mediaInvalidReasonCustomMessage Custom message when {@link #getMediaInvalidReason()} is set to
    *          {@link MediaInvalidReason#CUSTOM}. Message is interpreted as i18n key.
    */
-  public void setMediaInvalidReasonCustomMessage(String mediaInvalidReasonCustomMessage) {
+  public void setMediaInvalidReasonCustomMessage(@Nullable String mediaInvalidReasonCustomMessage) {
     this.mediaInvalidReasonCustomMessage = mediaInvalidReasonCustomMessage;
   }
 
diff --git a/src/main/java/io/wcm/handler/media/MediaComponentPropertyResolver.java b/src/main/java/io/wcm/handler/media/MediaComponentPropertyResolver.java
index 9690430c..fbd95198 100644
--- a/src/main/java/io/wcm/handler/media/MediaComponentPropertyResolver.java
+++ b/src/main/java/io/wcm/handler/media/MediaComponentPropertyResolver.java
@@ -193,7 +193,6 @@ else if (mediaFormatsMandatory.length > i) {
   /**
    * @return Image sizes
    */
-  @SuppressWarnings("null")
   public @Nullable ImageSizes getImageSizes() {
     String responsiveType = getResponsiveType();
     if (responsiveType != null && !StringUtils.equals(responsiveType, RESPONSIVE_TYPE_IMAGE_SIZES)) {
diff --git a/src/main/java/io/wcm/handler/media/MediaHandler.java b/src/main/java/io/wcm/handler/media/MediaHandler.java
index 0f53848b..0b7feb76 100644
--- a/src/main/java/io/wcm/handler/media/MediaHandler.java
+++ b/src/main/java/io/wcm/handler/media/MediaHandler.java
@@ -46,7 +46,7 @@ public interface MediaHandler {
    * @return Media builder
    */
   @NotNull
-  MediaBuilder get(Resource resource);
+  MediaBuilder get(@Nullable Resource resource);
 
   /**
    * Build media which is referenced in the resource (as property or inline binary data).
@@ -57,7 +57,7 @@ public interface MediaHandler {
    * @return Media builder
    */
   @NotNull
-  MediaBuilder get(Resource resource, MediaArgs mediaArgs);
+  MediaBuilder get(@Nullable Resource resource, @NotNull MediaArgs mediaArgs);
 
   /**
    * Build media which is referenced in the resource (as property or inline binary data).
@@ -68,7 +68,7 @@ public interface MediaHandler {
    * @return Media builder
    */
   @NotNull
-  MediaBuilder get(Resource resource, MediaFormat... mediaFormats);
+  MediaBuilder get(@Nullable Resource resource, MediaFormat @NotNull... mediaFormats);
 
   /**
    * Build media which is referenced via its string address.
@@ -78,7 +78,7 @@ public interface MediaHandler {
    * @see #get(String, Resource)
    */
   @NotNull
-  MediaBuilder get(String mediaRef);
+  MediaBuilder get(@Nullable String mediaRef);
 
   /**
    * Build media which is referenced via its string address.
@@ -88,7 +88,7 @@ public interface MediaHandler {
    * @return Media builder
    */
   @NotNull
-  MediaBuilder get(String mediaRef, @Nullable Resource contextResource);
+  MediaBuilder get(@Nullable String mediaRef, @Nullable Resource contextResource);
 
   /**
    * Build media which is referenced via its string address.
@@ -97,7 +97,7 @@ public interface MediaHandler {
    * @return Media builder
    */
   @NotNull
-  MediaBuilder get(String mediaRef, MediaArgs mediaArgs);
+  MediaBuilder get(@Nullable String mediaRef, @NotNull MediaArgs mediaArgs);
 
   /**
    * Build media which is referenced via its string address.
@@ -106,7 +106,7 @@ public interface MediaHandler {
    * @return Media builder
    */
   @NotNull
-  MediaBuilder get(String mediaRef, MediaFormat... mediaFormats);
+  MediaBuilder get(@Nullable String mediaRef, MediaFormat @NotNull... mediaFormats);
 
   /**
    * Build media for the given request holding all further request properties.
@@ -122,7 +122,7 @@ public interface MediaHandler {
    * @param element Media markup element.
    * @return true if media element is invalid
    */
-  boolean isValidElement(HtmlElement<?> element);
+  boolean isValidElement(@Nullable HtmlElement<?> element);
 
   /**
    * Returns an empty media that is marked as invalid.
diff --git a/src/main/java/io/wcm/handler/media/MediaNameConstants.java b/src/main/java/io/wcm/handler/media/MediaNameConstants.java
index 4ff421b7..a364cca1 100644
--- a/src/main/java/io/wcm/handler/media/MediaNameConstants.java
+++ b/src/main/java/io/wcm/handler/media/MediaNameConstants.java
@@ -19,7 +19,6 @@
  */
 package io.wcm.handler.media;
 
-import org.jetbrains.annotations.NotNull;
 import org.osgi.annotation.versioning.ProviderType;
 
 /**
@@ -46,117 +45,117 @@ private MediaNameConstants() {
   /**
    * Media format node type
    */
-  public static final @NotNull String NT_MEDIAFORMAT = "wcmio:MediaFormat";
+  public static final String NT_MEDIAFORMAT = "wcmio:MediaFormat";
 
   /**
    * Media source
    */
-  public static final @NotNull String PN_MEDIA_SOURCE = "mediaSource";
+  public static final String PN_MEDIA_SOURCE = "mediaSource";
 
   /**
    * Default property name for reference to media library item (Legacy wcm.io Handler Standard)
    */
-  public static final @NotNull String PN_MEDIA_REF = "mediaRef";
+  public static final String PN_MEDIA_REF = "mediaRef";
 
   /**
    * Default property name for reference to media library item (Adobe/Core Component standard)
    */
-  public static final @NotNull String PN_MEDIA_REF_STANDARD = "fileReference";
+  public static final String PN_MEDIA_REF_STANDARD = "fileReference";
 
   /**
    * Default property name for cropping parameters (Legacy wcm.io Handler Standard)
    */
-  public static final @NotNull String PN_MEDIA_CROP = "mediaCrop";
+  public static final String PN_MEDIA_CROP = "mediaCrop";
 
   /**
    * Default property name for cropping parameters (Adobe/Core Component standard)
    */
-  public static final @NotNull String PN_MEDIA_CROP_STANDARD = "imageCrop";
+  public static final String PN_MEDIA_CROP_STANDARD = "imageCrop";
 
   /**
    * Default property name for rotate parameter (Legacy wcm.io Handler Standard)
    */
-  public static final @NotNull String PN_MEDIA_ROTATION = "mediaRotate";
+  public static final String PN_MEDIA_ROTATION = "mediaRotate";
 
   /**
    * Default property name for rotate parameter (Adobe/Core Component standard)
    */
-  public static final @NotNull String PN_MEDIA_ROTATION_STANDARD = "imageRotate";
+  public static final String PN_MEDIA_ROTATION_STANDARD = "imageRotate";
 
   /**
    * Default property name for map parameter (Legacy wcm.io Handler Standard)
    */
-  public static final @NotNull String PN_MEDIA_MAP = "mediaMap";
+  public static final String PN_MEDIA_MAP = "mediaMap";
 
   /**
    * Default property name for map parameter (Adobe/Core Component standard)
    */
-  public static final @NotNull String PN_MEDIA_MAP_STANDARD = "imageMap";
+  public static final String PN_MEDIA_MAP_STANDARD = "imageMap";
 
   /**
    * Default property name for media alt. text (Legacy wcm.io Handler Standard)
    */
-  public static final @NotNull String PN_MEDIA_ALTTEXT = "mediaAltText";
+  public static final String PN_MEDIA_ALTTEXT = "mediaAltText";
 
   /**
    * Default property name for media alt. text (Adobe/Core Component standard)
    */
-  public static final @NotNull String PN_MEDIA_ALTTEXT_STANDARD = "alt";
+  public static final String PN_MEDIA_ALTTEXT_STANDARD = "alt";
 
   /**
    * Default property name for forcing reading alt. text from DAM asset description (Legacy wcm.io Handler Standard)
    */
-  public static final @NotNull String PN_MEDIA_FORCE_ALTTEXT_FROM_ASSET = "mediaForceAltValueFromAsset";
+  public static final String PN_MEDIA_FORCE_ALTTEXT_FROM_ASSET = "mediaForceAltValueFromAsset";
 
   /**
    * Default property name for forcing reading alt. text from DAM asset description (Adobe/Core Component standard)
    */
-  public static final @NotNull String PN_MEDIA_FORCE_ALTTEXT_FROM_ASSET_STANDARD = "altValueFromDAM";
+  public static final String PN_MEDIA_FORCE_ALTTEXT_FROM_ASSET_STANDARD = "altValueFromDAM";
 
   /**
    * Default property name for marking image as "decorative" - requiring no alt. text (Legacy wcm.io Handler Standard)
    */
-  public static final @NotNull String PN_MEDIA_IS_DECORATIVE = "mediaIsDecorative";
+  public static final String PN_MEDIA_IS_DECORATIVE = "mediaIsDecorative";
 
   /**
    * Default property name for marking image as "decorative" - requiring no alt. text (Adobe/Core Component standard)
    */
-  public static final @NotNull String PN_MEDIA_IS_DECORATIVE_STANDARD = "isDecorative";
+  public static final String PN_MEDIA_IS_DECORATIVE_STANDARD = "isDecorative";
 
   /**
    * Default node name for inline media item stored in node within the content page (Legacy wcm.io Handler Standard)
    */
-  public static final @NotNull String NN_MEDIA_INLINE = "mediaInline";
+  public static final String NN_MEDIA_INLINE = "mediaInline";
 
   /**
    * Default node name for inline media item stored in node within the content page (Adobe/Core Component standard)
    */
-  public static final @NotNull String NN_MEDIA_INLINE_STANDARD = "file";
+  public static final String NN_MEDIA_INLINE_STANDARD = "file";
 
   /**
    * CSS class for dummy image
    */
-  public static final @NotNull String CSS_DUMMYIMAGE = "wcmio_mediahandler_wcm_dummy";
+  public static final String CSS_DUMMYIMAGE = "wcmio_mediahandler_wcm_dummy";
 
   /**
    * CSS class for "Added in Diff Mode"
    */
-  public static final @NotNull String CSS_DIFF_ADDED = "wcmio_mediahandler_wcm_diff_added";
+  public static final String CSS_DIFF_ADDED = "wcmio_mediahandler_wcm_diff_added";
 
   /**
    * CSS class for "Updated in Diff Mode"
    */
-  public static final @NotNull String CSS_DIFF_UPDATED = "wcmio_mediahandler_wcm_diff_updated";
+  public static final String CSS_DIFF_UPDATED = "wcmio_mediahandler_wcm_diff_updated";
 
   /**
    * CSS class for "Removed in Diff Mode"
    */
-  public static final @NotNull String CSS_DIFF_REMOVED = "wcmio_mediahandler_wcm_diff_removed";
+  public static final String CSS_DIFF_REMOVED = "wcmio_mediahandler_wcm_diff_removed";
 
   /**
    * Property name for setting additional CSS classes
    */
-  public static final @NotNull String PROP_CSS_CLASS = "cssClass";
+  public static final String PROP_CSS_CLASS = "cssClass";
 
   /**
    * Enable "auto-cropping" mode for this component by setting to true.
@@ -164,7 +163,7 @@ private MediaNameConstants() {
    * Property is to be set on component or in policy.
    * </p>
    */
-  public static final @NotNull String PN_COMPONENT_MEDIA_AUTOCROP = "wcmio:mediaCropAuto";
+  public static final String PN_COMPONENT_MEDIA_AUTOCROP = "wcmio:mediaCropAuto";
 
   /**
    * List of media format names accepted by this component.
@@ -172,7 +171,7 @@ private MediaNameConstants() {
    * Property is to be set on component or in policy.
    * </p>
    */
-  public static final @NotNull String PN_COMPONENT_MEDIA_FORMATS = "wcmio:mediaFormats";
+  public static final String PN_COMPONENT_MEDIA_FORMATS = "wcmio:mediaFormats";
 
   /**
    * Resolving of all media formats is mandatory. This can be a single boolean, or a boolean array
@@ -181,7 +180,7 @@ private MediaNameConstants() {
    * Property is to be set on component or in policy.
    * </p>
    */
-  public static final @NotNull String PN_COMPONENT_MEDIA_FORMATS_MANDATORY = "wcmio:mediaFormatsMandatory";
+  public static final String PN_COMPONENT_MEDIA_FORMATS_MANDATORY = "wcmio:mediaFormatsMandatory";
 
   /**
    * List of media format names that are mandatory. The list of names is merged with the list
@@ -191,7 +190,7 @@ private MediaNameConstants() {
    * Property is to be set on component or in policy.
    * </p>
    */
-  public static final @NotNull String PN_COMPONENT_MEDIA_FORMATS_MANDATORY_NAMES = "wcmio:mediaFormatsMandatoryNames";
+  public static final String PN_COMPONENT_MEDIA_FORMATS_MANDATORY_NAMES = "wcmio:mediaFormatsMandatoryNames";
 
   /**
    * If multiple responsive image settings are defined, this property defines which gets active.
@@ -200,7 +199,7 @@ private MediaNameConstants() {
    * Property is to be set on component or in policy.
    * </p>
    */
-  public static final @NotNull String PN_COMPONENT_MEDIA_RESPONSIVE_TYPE = "wcmio:mediaResponsiveType";
+  public static final String PN_COMPONENT_MEDIA_RESPONSIVE_TYPE = "wcmio:mediaResponsiveType";
 
   /**
    * Defines "image sizes" responsive image setting.
@@ -209,7 +208,7 @@ private MediaNameConstants() {
    * Child node is to be defined on component or in policy.
    * </p>
    */
-  public static final @NotNull String NN_COMPONENT_MEDIA_RESPONSIVEIMAGE_SIZES = "wcmio:mediaResponsiveImageSizes";
+  public static final String NN_COMPONENT_MEDIA_RESPONSIVEIMAGE_SIZES = "wcmio:mediaResponsiveImageSizes";
 
   /**
    * Defines "picture sources" responsive image setting.
@@ -219,7 +218,7 @@ private MediaNameConstants() {
    * Child node is to be defined on component or in policy.
    * </p>
    */
-  public static final @NotNull String NN_COMPONENT_MEDIA_RESPONSIVEPICTURE_SOURCES = "wcmio:mediaResponsivePictureSources";
+  public static final String NN_COMPONENT_MEDIA_RESPONSIVEPICTURE_SOURCES = "wcmio:mediaResponsivePictureSources";
 
   /**
    * Media format property name for the parent media format. Parent media format is the original media format that
diff --git a/src/main/java/io/wcm/handler/media/UriTemplate.java b/src/main/java/io/wcm/handler/media/UriTemplate.java
index de774a97..60227511 100644
--- a/src/main/java/io/wcm/handler/media/UriTemplate.java
+++ b/src/main/java/io/wcm/handler/media/UriTemplate.java
@@ -19,6 +19,7 @@
  */
 package io.wcm.handler.media;
 
+import org.jetbrains.annotations.NotNull;
 import org.osgi.annotation.versioning.ProviderType;
 
 /**
@@ -30,11 +31,13 @@ public interface UriTemplate {
   /**
    * @return URI template string containing placeholders like <code>{width}</code> or <code>{height}</code>.
    */
+  @NotNull
   String getUriTemplate();
 
   /**
    * @return URI template type
    */
+  @NotNull
   UriTemplateType getType();
 
   /**
diff --git a/src/main/java/io/wcm/handler/media/impl/MediaFormatValidateServlet.java b/src/main/java/io/wcm/handler/media/impl/MediaFormatValidateServlet.java
index 340e698b..50106c9a 100644
--- a/src/main/java/io/wcm/handler/media/impl/MediaFormatValidateServlet.java
+++ b/src/main/java/io/wcm/handler/media/impl/MediaFormatValidateServlet.java
@@ -126,11 +126,15 @@ protected void doGet(@NotNull SlingHttpServletRequest request, @NotNull SlingHtt
   }
 
   private String getMediaInvalidReasonI18nKeyOrMessage(@NotNull Media media) {
-    if (media.getMediaInvalidReason() == MediaInvalidReason.CUSTOM) {
+    MediaInvalidReason reason = media.getMediaInvalidReason();
+    if (reason == MediaInvalidReason.CUSTOM) {
       return media.getMediaInvalidReasonCustomMessage();
     }
+    else if (reason != null) {
+      return MEDIA_INVALID_REASON_I18N_PREFIX + reason.name();
+    }
     else {
-      return MEDIA_INVALID_REASON_I18N_PREFIX + media.getMediaInvalidReason().name();
+      return "";
     }
   }
 
diff --git a/src/main/java/io/wcm/handler/media/impl/MediaHandlerImpl.java b/src/main/java/io/wcm/handler/media/impl/MediaHandlerImpl.java
index 4ad4e523..20d81d38 100644
--- a/src/main/java/io/wcm/handler/media/impl/MediaHandlerImpl.java
+++ b/src/main/java/io/wcm/handler/media/impl/MediaHandlerImpl.java
@@ -70,37 +70,37 @@ public final class MediaHandlerImpl implements MediaHandler {
   private static final Logger log = LoggerFactory.getLogger(MediaHandlerImpl.class);
 
   @Override
-  public @NotNull MediaBuilder get(Resource resource) {
+  public @NotNull MediaBuilder get(@Nullable Resource resource) {
     return new MediaBuilderImpl(resource, this, componentPropertyResolverFactory);
   }
 
   @Override
-  public @NotNull MediaBuilder get(Resource resource, MediaArgs mediaArgs) {
+  public @NotNull MediaBuilder get(@Nullable Resource resource, @NotNull MediaArgs mediaArgs) {
     return get(resource).args(mediaArgs);
   }
 
   @Override
-  public @NotNull MediaBuilder get(Resource resource, MediaFormat... mediaFormats) {
+  public @NotNull MediaBuilder get(@Nullable Resource resource, MediaFormat @NotNull... mediaFormats) {
     return get(resource).mediaFormats(mediaFormats);
   }
 
   @Override
-  public @NotNull MediaBuilder get(String mediaRef) {
+  public @NotNull MediaBuilder get(@Nullable String mediaRef) {
     return new MediaBuilderImpl(mediaRef, null, this, componentPropertyResolverFactory);
   }
 
   @Override
-  public @NotNull MediaBuilder get(String mediaRef, @Nullable Resource contextResource) {
+  public @NotNull MediaBuilder get(@Nullable String mediaRef, @Nullable Resource contextResource) {
     return new MediaBuilderImpl(mediaRef, contextResource, this, componentPropertyResolverFactory);
   }
 
   @Override
-  public @NotNull MediaBuilder get(String mediaRef, MediaArgs mediaArgs) {
+  public @NotNull MediaBuilder get(@Nullable String mediaRef, @NotNull MediaArgs mediaArgs) {
     return get(mediaRef).args(mediaArgs);
   }
 
   @Override
-  public @NotNull MediaBuilder get(String mediaRef, MediaFormat... mediaFormats) {
+  public @NotNull MediaBuilder get(@Nullable String mediaRef, MediaFormat @NotNull... mediaFormats) {
     return get(mediaRef).mediaFormats(mediaFormats);
   }
 
diff --git a/src/main/java/io/wcm/handler/media/impl/WidthUtils.java b/src/main/java/io/wcm/handler/media/impl/WidthUtils.java
index bede57f9..7071656f 100644
--- a/src/main/java/io/wcm/handler/media/impl/WidthUtils.java
+++ b/src/main/java/io/wcm/handler/media/impl/WidthUtils.java
@@ -27,7 +27,6 @@
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
-import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
 import io.wcm.handler.media.MediaArgs.WidthOption;
 
 /**
@@ -49,8 +48,7 @@ private WidthUtils() {
    * @param widths Width string
    * @return Width options
    */
-  @SuppressFBWarnings("NP_NONNULL_RETURN_VIOLATION")
-  public static @NotNull WidthOption @Nullable [] parseWidths(@Nullable String widths) {
+  public static @Nullable WidthOption @Nullable [] parseWidths(@Nullable String widths) {
     if (StringUtils.isBlank(widths)) {
       return null;
     }
diff --git a/src/main/java/io/wcm/handler/media/markup/SimpleImageMediaMarkupBuilder.java b/src/main/java/io/wcm/handler/media/markup/SimpleImageMediaMarkupBuilder.java
index ad24bb55..96fe7e3c 100644
--- a/src/main/java/io/wcm/handler/media/markup/SimpleImageMediaMarkupBuilder.java
+++ b/src/main/java/io/wcm/handler/media/markup/SimpleImageMediaMarkupBuilder.java
@@ -70,9 +70,10 @@ public class SimpleImageMediaMarkupBuilder extends AbstractImageMediaMarkupBuild
   @Override
   public final boolean accepts(@NotNull Media media) {
     // accept if rendition is an image rendition, and resolving was successful
+    Rendition rendition = media.getRendition();
     return media.isValid()
-        && media.getRendition() != null
-        && media.getRendition().isBrowserImage();
+        && rendition != null
+        && rendition.isBrowserImage();
   }
 
   @Override
diff --git a/src/main/java/io/wcm/handler/media/spi/MediaFormatProvider.java b/src/main/java/io/wcm/handler/media/spi/MediaFormatProvider.java
index c3b0c8a3..223c2642 100644
--- a/src/main/java/io/wcm/handler/media/spi/MediaFormatProvider.java
+++ b/src/main/java/io/wcm/handler/media/spi/MediaFormatProvider.java
@@ -24,6 +24,7 @@
 import java.util.HashSet;
 import java.util.Set;
 
+import org.jetbrains.annotations.NotNull;
 import org.osgi.annotation.versioning.ConsumerType;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -60,7 +61,7 @@ protected MediaFormatProvider(Class<?> type) {
   /**
    * @return Media formats that the application defines
    */
-  public Set<MediaFormat> getMediaFormats() {
+  public @NotNull Set<MediaFormat> getMediaFormats() {
     return mediaFormats;
   }
 
diff --git a/src/main/java/io/wcm/handler/media/ui/ImageUtils.java b/src/main/java/io/wcm/handler/media/ui/ImageUtils.java
index 53807c38..0281a917 100644
--- a/src/main/java/io/wcm/handler/media/ui/ImageUtils.java
+++ b/src/main/java/io/wcm/handler/media/ui/ImageUtils.java
@@ -24,6 +24,7 @@
 import org.apache.commons.lang3.BooleanUtils;
 import org.apache.commons.lang3.StringUtils;
 import org.apache.commons.lang3.math.NumberUtils;
+import org.jetbrains.annotations.NotNull;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -50,8 +51,8 @@ private ImageUtils() {
    * @param medias             media expressions for the picture source elements
    * @param widths             widths for the picture source elements
    */
-  public static void applyPictureSources(MediaFormatHandler mediaFormatHandler, MediaBuilder builder,
-      String[] mediaFormatNames, String[] medias, String[] widths) {
+  public static void applyPictureSources(@NotNull MediaFormatHandler mediaFormatHandler, @NotNull MediaBuilder builder,
+      String @NotNull [] mediaFormatNames, String @NotNull [] medias, String @NotNull [] widths) {
     for (int i = 0; i < mediaFormatNames.length && i < medias.length && i < widths.length; i++) {
       MediaFormat mediaFormat = mediaFormatHandler.getMediaFormat(mediaFormatNames[i]);
       if (mediaFormat != null) {
@@ -79,7 +80,7 @@ public static void applyPictureSources(MediaFormatHandler mediaFormatHandler, Me
    * @param widths Widths string
    * @return Widths array
    */
-  public static long[] toWidthsArray(String widths) {
+  public static long[] toWidthsArray(@NotNull String widths) {
     if (StringUtils.isBlank(widths)) {
       return new long[0];
     }
@@ -97,7 +98,7 @@ public static long[] toWidthsArray(String widths) {
    * @param widthOptions Width options string
    * @return Widths array which is empty in case given widthOptions is blank
    */
-  public static MediaArgs.WidthOption[] toWidthOptionArray(String widthOptions) {
+  public static MediaArgs.WidthOption[] toWidthOptionArray(@NotNull String widthOptions) {
     if (StringUtils.isBlank(widthOptions)) {
       return new MediaArgs.WidthOption[0];
     }
diff --git a/src/main/java/io/wcm/handler/media/ui/MediaPlaceholder.java b/src/main/java/io/wcm/handler/media/ui/MediaPlaceholder.java
index f40ba524..6c21834f 100644
--- a/src/main/java/io/wcm/handler/media/ui/MediaPlaceholder.java
+++ b/src/main/java/io/wcm/handler/media/ui/MediaPlaceholder.java
@@ -99,10 +99,10 @@ private String getMediaDropCssClass(Media mediaMetadata) {
   }
 
   private String getMediaInvalidReasonText(Media mediaMetadata) {
-    if (mediaMetadata.getMediaInvalidReason() != null
-        && mediaMetadata.getMediaInvalidReason() != MediaInvalidReason.MEDIA_REFERENCE_MISSING) {
+    MediaInvalidReason reason = mediaMetadata.getMediaInvalidReason();
+    if (reason != null && reason != MediaInvalidReason.MEDIA_REFERENCE_MISSING) {
       // build i18n key
-      return MEDIA_INVALID_REASON_I18N_PREFIX + mediaMetadata.getMediaInvalidReason().name();
+      return MEDIA_INVALID_REASON_I18N_PREFIX + reason.name();
     }
     else {
       return null;
diff --git a/src/main/java/io/wcm/handler/mediasource/dam/impl/DamUriTemplate.java b/src/main/java/io/wcm/handler/mediasource/dam/impl/DamUriTemplate.java
index 00bee5a0..5be2e84c 100644
--- a/src/main/java/io/wcm/handler/mediasource/dam/impl/DamUriTemplate.java
+++ b/src/main/java/io/wcm/handler/mediasource/dam/impl/DamUriTemplate.java
@@ -204,12 +204,12 @@ private static NamedDimension getDynamicMediaSmartCropDef(@Nullable CropDimensio
   }
 
   @Override
-  public UriTemplateType getType() {
+  public @NotNull UriTemplateType getType() {
     return type;
   }
 
   @Override
-  public String getUriTemplate() {
+  public @NotNull String getUriTemplate() {
     return uriTemplate;
   }
 
diff --git a/src/main/java/io/wcm/handler/mediasource/dam/markup/DamVideoMediaMarkupBuilder.java b/src/main/java/io/wcm/handler/mediasource/dam/markup/DamVideoMediaMarkupBuilder.java
index 4227df35..24ef6d2f 100644
--- a/src/main/java/io/wcm/handler/mediasource/dam/markup/DamVideoMediaMarkupBuilder.java
+++ b/src/main/java/io/wcm/handler/mediasource/dam/markup/DamVideoMediaMarkupBuilder.java
@@ -33,6 +33,7 @@
 import org.apache.sling.models.annotations.injectorspecific.Self;
 import org.apache.sling.models.annotations.injectorspecific.SlingObject;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 import org.osgi.annotation.versioning.ConsumerType;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -123,8 +124,12 @@ private VideoProfile getVideoProfile(String profileName) {
    * @param media Media metadata
    * @return DAM asset or null
    */
-  protected Asset getDamAsset(Media media) {
-    return media.getAsset().adaptTo(Asset.class);
+  protected @Nullable Asset getDamAsset(Media media) {
+    io.wcm.handler.media.Asset asset = media.getAsset();
+    if (asset != null) {
+      return asset.adaptTo(Asset.class);
+    }
+    return null;
   }
 
   @Override
diff --git a/src/main/java/io/wcm/handler/mediasource/inline/InlineUriTemplate.java b/src/main/java/io/wcm/handler/mediasource/inline/InlineUriTemplate.java
index 807f2517..f2e47935 100644
--- a/src/main/java/io/wcm/handler/mediasource/inline/InlineUriTemplate.java
+++ b/src/main/java/io/wcm/handler/mediasource/inline/InlineUriTemplate.java
@@ -99,12 +99,12 @@ private static String buildUriTemplate(@NotNull UriTemplateType type, @NotNull R
   }
 
   @Override
-  public UriTemplateType getType() {
+  public @NotNull UriTemplateType getType() {
     return type;
   }
 
   @Override
-  public String getUriTemplate() {
+  public @NotNull String getUriTemplate() {
     return uriTemplate;
   }
 
diff --git a/src/test/java/io/wcm/handler/media/impl/MediaHandlerImplImageFileTypesEnd2EndTest.java b/src/test/java/io/wcm/handler/media/impl/MediaHandlerImplImageFileTypesEnd2EndTest.java
index e69a861a..1cf41435 100644
--- a/src/test/java/io/wcm/handler/media/impl/MediaHandlerImplImageFileTypesEnd2EndTest.java
+++ b/src/test/java/io/wcm/handler/media/impl/MediaHandlerImplImageFileTypesEnd2EndTest.java
@@ -445,6 +445,7 @@ void buildAssertInvalidMedia_AutoCrop(Asset asset) {
     assertFalse(media.isValid(), "media valid");
   }
 
+  @SuppressWarnings("null")
   void assertMedia(Resource resource, Media media, int width, int height, String mediaUrl, String contentType) {
     assertTrue(media.isValid(), "media valid");
     assertEquals(mediaUrl, media.getUrl(), "mediaUrl");
diff --git a/src/test/java/io/wcm/handler/media/testcontext/UriTemplateAssert.java b/src/test/java/io/wcm/handler/media/testcontext/UriTemplateAssert.java
index 797ebbf7..392ef33d 100644
--- a/src/test/java/io/wcm/handler/media/testcontext/UriTemplateAssert.java
+++ b/src/test/java/io/wcm/handler/media/testcontext/UriTemplateAssert.java
@@ -23,6 +23,7 @@
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import io.wcm.handler.media.Asset;
 import io.wcm.handler.media.Media;
 import io.wcm.handler.media.Rendition;
 import io.wcm.handler.media.UriTemplate;
@@ -40,7 +41,9 @@ private UriTemplateAssert() {
   public static void assertUriTemplate(Media media, UriTemplateType type,
       long expectedMaxWith, long expectedMaxHeight, String expectedTemplate) {
     assertTrue(media.isValid(), "media valid");
-    UriTemplate uriTemplate = media.getAsset().getUriTemplate(type);
+    Asset asset = media.getAsset();
+    assertNotNull(asset);
+    UriTemplate uriTemplate = asset.getUriTemplate(type);
     assertEquals(type, uriTemplate.getType(), "uriTemplateType");
     assertEquals(expectedMaxWith, uriTemplate.getMaxWidth(), "maxWidth(" + type + ")");
     assertEquals(expectedMaxHeight, uriTemplate.getMaxHeight(), "maxHeight(" + type + ")");
diff --git a/src/test/java/io/wcm/handler/mediasource/dam/DamUriTemplateRenditionTest.java b/src/test/java/io/wcm/handler/mediasource/dam/DamUriTemplateRenditionTest.java
index 809d8709..9bd85da9 100644
--- a/src/test/java/io/wcm/handler/mediasource/dam/DamUriTemplateRenditionTest.java
+++ b/src/test/java/io/wcm/handler/mediasource/dam/DamUriTemplateRenditionTest.java
@@ -88,6 +88,7 @@ void setUp() {
   }
 
   @Test
+  @SuppressWarnings("null")
   void testOriginal_CropCenter() {
     Asset asset = createSampleAsset();
     Media media = mediaHandler.get(asset.getPath())
diff --git a/src/test/java/io/wcm/handler/mediasource/dam/impl/AssertThumbnailWebRenditionMediaHandlerTest.java b/src/test/java/io/wcm/handler/mediasource/dam/impl/AssertThumbnailWebRenditionMediaHandlerTest.java
index 1f7265d7..f52d8deb 100644
--- a/src/test/java/io/wcm/handler/mediasource/dam/impl/AssertThumbnailWebRenditionMediaHandlerTest.java
+++ b/src/test/java/io/wcm/handler/mediasource/dam/impl/AssertThumbnailWebRenditionMediaHandlerTest.java
@@ -72,7 +72,7 @@ void setUp() {
   }
 
   @Test
-  @SuppressWarnings("deprecation")
+  @SuppressWarnings({ "deprecation", "null" })
   void testWithAllowWebRenditions() {
     mediaHandler = AdaptTo.notNull(context.request(), MediaHandler.class);
 
@@ -89,7 +89,7 @@ void testWithAllowWebRenditions() {
   }
 
   @Test
-  @SuppressWarnings("deprecation")
+  @SuppressWarnings({ "deprecation", "null" })
   void testWithDisallowWebRenditions() {
     mediaHandler = AdaptTo.notNull(context.request(), MediaHandler.class);
 
@@ -106,7 +106,7 @@ void testWithDisallowWebRenditions() {
   }
 
   @Test
-  @SuppressWarnings("deprecation")
+  @SuppressWarnings({ "deprecation", "null" })
   void testWithAllowThumbnailRenditions() {
     mediaHandler = AdaptTo.notNull(context.request(), MediaHandler.class);
 
@@ -123,6 +123,7 @@ void testWithAllowThumbnailRenditions() {
   }
 
   @Test
+  @SuppressWarnings("null")
   void testWithAllowSpecificRenditions() {
     mediaHandler = AdaptTo.notNull(context.request(), MediaHandler.class);
 
@@ -139,6 +140,7 @@ void testWithAllowSpecificRenditions() {
   }
 
   @Test
+  @SuppressWarnings("null")
   void testWithDisallowWebRenditionsViaMediaHandlerConfig() {
     context.registerService(MediaHandlerConfig.class, new MediaHandlerConfig() {
       @Override
diff --git a/src/test/java/io/wcm/handler/mediasource/dam/impl/AutoCroppingMediaHandlerTest.java b/src/test/java/io/wcm/handler/mediasource/dam/impl/AutoCroppingMediaHandlerTest.java
index 1cf0da6a..bff652ba 100644
--- a/src/test/java/io/wcm/handler/mediasource/dam/impl/AutoCroppingMediaHandlerTest.java
+++ b/src/test/java/io/wcm/handler/mediasource/dam/impl/AutoCroppingMediaHandlerTest.java
@@ -80,6 +80,7 @@ void setUp() {
   }
 
   @Test
+  @SuppressWarnings("null")
   void testMediaFormatWithRatio() {
     Media media = mediaHandler.get(resource)
         .mediaFormat(RATIO_16_10)
@@ -92,6 +93,7 @@ void testMediaFormatWithRatio() {
   }
 
   @Test
+  @SuppressWarnings("null")
   void testMediaFormatFixedDimension() {
     Media media = mediaHandler.get(resource)
         .mediaFormat(EDITORIAL_1COL)
@@ -104,6 +106,7 @@ void testMediaFormatFixedDimension() {
   }
 
   @Test
+  @SuppressWarnings("null")
   void testMultipleMediaFormatsFixedDimension() {
     Media media = mediaHandler.get(resource)
         .mediaFormats(EDITORIAL_2COL, EDITORIAL_1COL)
@@ -124,8 +127,8 @@ void testMediaFormatFixedDimension_NoMatch() {
   }
 
   @Test
+  @SuppressWarnings("null")
   void testManualCroppingParametersHaveHigherPrecedence() {
-
     // prepare resource with asset reference and manual cropping parameters
     // this manual cropping results in a 16:10 image and should have higher precedence than auto-cropping
     Resource resource2 = context.create().resource("/content/test2",
@@ -144,8 +147,8 @@ void testManualCroppingParametersHaveHigherPrecedence() {
   }
 
   @Test
+  @SuppressWarnings("null")
   void testInvalidManualCroppingParametersFallbackToAutoCropping() {
-
     // prepare resource with asset reference and manual cropping parameters
     // this manual cropping results in a 1:1 image not matching the media format
     Resource resource2 = context.create().resource("/content/test2",
@@ -165,7 +168,7 @@ void testInvalidManualCroppingParametersFallbackToAutoCropping() {
   }
 
   @Test
-  @SuppressWarnings("deprecation")
+  @SuppressWarnings({ "deprecation", "null" })
   void testMediaFormatWithRatio_WebRenditionsExcludedFromMediaHandling() {
     Media media = mediaHandler.get(resource)
         .mediaFormat(RATIO_16_10)
diff --git a/src/test/java/io/wcm/handler/mediasource/inline/InlineUriTemplateRenditionTest.java b/src/test/java/io/wcm/handler/mediasource/inline/InlineUriTemplateRenditionTest.java
index 44249da9..942749e6 100644
--- a/src/test/java/io/wcm/handler/mediasource/inline/InlineUriTemplateRenditionTest.java
+++ b/src/test/java/io/wcm/handler/mediasource/inline/InlineUriTemplateRenditionTest.java
@@ -73,6 +73,7 @@ void setUp() {
   }
 
   @Test
+  @SuppressWarnings("null")
   void testOriginal_CropCenter() {
     Media media = mediaHandler.get(inlineImage)
         .mediaFormat(RATIO_16_10)