diff --git a/Examples/Java/Sources/Board.java b/Examples/Java/Sources/Board.java
index 25f588ca..bf34b62b 100644
--- a/Examples/Java/Sources/Board.java
+++ b/Examples/Java/Sources/Board.java
@@ -82,15 +82,18 @@ private Board(
         this._bits = _bits;
     }
 
+    @NonNull
     public static Board.Builder builder() {
         return new Board.Builder();
     }
 
+    @NonNull
     public Board.Builder toBuilder() {
         return new Board.Builder(this);
     }
 
-    public Board mergeFrom(Board model) {
+    @NonNull
+    public Board mergeFrom(@NonNull Board model) {
         Board.Builder builder = this.toBuilder();
         builder.mergeFrom(model);
         return builder.build();
@@ -243,6 +246,7 @@ private Builder(@NonNull Board model) {
             this._bits = model._bits;
         }
 
+        @NonNull
         public Builder setUid(@Nullable String value) {
             this.uid = value;
             if (this._bits.length > ID_INDEX) {
@@ -251,6 +255,7 @@ public Builder setUid(@Nullable String value) {
             return this;
         }
 
+        @NonNull
         public Builder setContributors(@Nullable Set<User> value) {
             this.contributors = value;
             if (this._bits.length > CONTRIBUTORS_INDEX) {
@@ -259,6 +264,7 @@ public Builder setContributors(@Nullable Set<User> value) {
             return this;
         }
 
+        @NonNull
         public Builder setCounts(@Nullable Map<String, Integer> value) {
             this.counts = value;
             if (this._bits.length > COUNTS_INDEX) {
@@ -267,6 +273,7 @@ public Builder setCounts(@Nullable Map<String, Integer> value) {
             return this;
         }
 
+        @NonNull
         public Builder setCreatedAt(@Nullable Date value) {
             this.createdAt = value;
             if (this._bits.length > CREATED_AT_INDEX) {
@@ -275,6 +282,7 @@ public Builder setCreatedAt(@Nullable Date value) {
             return this;
         }
 
+        @NonNull
         public Builder setCreator(@Nullable Map<String, String> value) {
             this.creator = value;
             if (this._bits.length > CREATOR_INDEX) {
@@ -283,6 +291,7 @@ public Builder setCreator(@Nullable Map<String, String> value) {
             return this;
         }
 
+        @NonNull
         public Builder setCreatorURL(@Nullable String value) {
             this.creatorURL = value;
             if (this._bits.length > CREATOR_URL_INDEX) {
@@ -291,6 +300,7 @@ public Builder setCreatorURL(@Nullable String value) {
             return this;
         }
 
+        @NonNull
         public Builder setDescription(@Nullable String value) {
             this.description = value;
             if (this._bits.length > DESCRIPTION_INDEX) {
@@ -299,6 +309,7 @@ public Builder setDescription(@Nullable String value) {
             return this;
         }
 
+        @NonNull
         public Builder setImage(@NonNull Image value) {
             this.image = value;
             if (this._bits.length > IMAGE_INDEX) {
@@ -307,6 +318,7 @@ public Builder setImage(@NonNull Image value) {
             return this;
         }
 
+        @NonNull
         public Builder setName(@Nullable String value) {
             this.name = value;
             if (this._bits.length > NAME_INDEX) {
@@ -315,6 +327,7 @@ public Builder setName(@Nullable String value) {
             return this;
         }
 
+        @NonNull
         public Builder setUrl(@Nullable String value) {
             this.url = value;
             if (this._bits.length > URL_INDEX) {
@@ -380,7 +393,7 @@ public Board build() {
             );
         }
 
-        public void mergeFrom(Board model) {
+        public void mergeFrom(@NonNull Board model) {
             if (model.getUidIsSet()) {
                 this.uid = model.uid;
                 if (this._bits.length > ID_INDEX) {
@@ -446,8 +459,9 @@ public void mergeFrom(Board model) {
 
     public static class BoardTypeAdapterFactory implements TypeAdapterFactory {
 
+        @Nullable
         @Override
-        public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) {
+        public <T> TypeAdapter<T> create(@NonNull Gson gson, @NonNull TypeToken<T> typeToken) {
             if (!Board.class.isAssignableFrom(typeToken.getRawType())) {
                 return null;
             }
@@ -469,14 +483,14 @@ public static class BoardTypeAdapter extends TypeAdapter<Board> {
         private TypeAdapter<Set<User>> set_User_TypeAdapter;
         private TypeAdapter<String> stringTypeAdapter;
 
-        public BoardTypeAdapter(Gson gson, BoardTypeAdapterFactory factory, TypeToken typeToken) {
+        public BoardTypeAdapter(@NonNull Gson gson, BoardTypeAdapterFactory factory, TypeToken typeToken) {
             this.factory = factory;
             this.gson = gson;
             this.typeToken = typeToken;
         }
 
         @Override
-        public void write(JsonWriter writer, Board value) throws IOException {
+        public void write(@NonNull JsonWriter writer, Board value) throws IOException {
             if (this.delegateTypeAdapter == null) {
                 this.delegateTypeAdapter = this.gson.getDelegateAdapter(this.factory, this.typeToken);
             }
@@ -484,8 +498,9 @@ public void write(JsonWriter writer, Board value) throws IOException {
             this.delegateTypeAdapter.write(writer, value);
         }
 
+        @Nullable
         @Override
-        public Board read(JsonReader reader) throws IOException {
+        public Board read(@NonNull JsonReader reader) throws IOException {
             if (reader.peek() == JsonToken.NULL) {
                 reader.nextNull();
                 return null;
diff --git a/Examples/Java/Sources/Everything.java b/Examples/Java/Sources/Everything.java
index 2d56372b..03ceeaf8 100644
--- a/Examples/Java/Sources/Everything.java
+++ b/Examples/Java/Sources/Everything.java
@@ -305,15 +305,18 @@ private Everything(
         this._bits = _bits;
     }
 
+    @NonNull
     public static Everything.Builder builder() {
         return new Everything.Builder();
     }
 
+    @NonNull
     public Everything.Builder toBuilder() {
         return new Everything.Builder(this);
     }
 
-    public Everything mergeFrom(Everything model) {
+    @NonNull
+    public Everything mergeFrom(@NonNull Everything model) {
         Everything.Builder builder = this.toBuilder();
         builder.mergeFrom(model);
         return builder.build();
@@ -781,6 +784,7 @@ private Builder(@NonNull Everything model) {
             this._bits = model._bits;
         }
 
+        @NonNull
         public Builder setArrayProp(@Nullable List<Object> value) {
             this.arrayProp = value;
             if (this._bits.length > ARRAY_PROP_INDEX) {
@@ -789,6 +793,7 @@ public Builder setArrayProp(@Nullable List<Object> value) {
             return this;
         }
 
+        @NonNull
         public Builder setBooleanProp(@Nullable Boolean value) {
             this.booleanProp = value;
             if (this._bits.length > BOOLEAN_PROP_INDEX) {
@@ -797,6 +802,7 @@ public Builder setBooleanProp(@Nullable Boolean value) {
             return this;
         }
 
+        @NonNull
         public Builder setCharEnum(@Nullable EverythingCharEnum value) {
             this.charEnum = value;
             if (this._bits.length > CHAR_ENUM_INDEX) {
@@ -805,6 +811,7 @@ public Builder setCharEnum(@Nullable EverythingCharEnum value) {
             return this;
         }
 
+        @NonNull
         public Builder setDateProp(@Nullable Date value) {
             this.dateProp = value;
             if (this._bits.length > DATE_PROP_INDEX) {
@@ -813,6 +820,7 @@ public Builder setDateProp(@Nullable Date value) {
             return this;
         }
 
+        @NonNull
         public Builder setIntEnum(@Nullable EverythingIntEnum value) {
             this.intEnum = value;
             if (this._bits.length > INT_ENUM_INDEX) {
@@ -821,6 +829,7 @@ public Builder setIntEnum(@Nullable EverythingIntEnum value) {
             return this;
         }
 
+        @NonNull
         public Builder setIntProp(@Nullable Integer value) {
             this.intProp = value;
             if (this._bits.length > INT_PROP_INDEX) {
@@ -829,6 +838,7 @@ public Builder setIntProp(@Nullable Integer value) {
             return this;
         }
 
+        @NonNull
         public Builder setListPolymorphicValues(@Nullable List<Object> value) {
             this.listPolymorphicValues = value;
             if (this._bits.length > LIST_POLYMORPHIC_VALUES_INDEX) {
@@ -837,6 +847,7 @@ public Builder setListPolymorphicValues(@Nullable List<Object> value) {
             return this;
         }
 
+        @NonNull
         public Builder setListWithListAndOtherModelValues(@Nullable List<List<User>> value) {
             this.listWithListAndOtherModelValues = value;
             if (this._bits.length > LIST_WITH_LIST_AND_OTHER_MODEL_VALUES_INDEX) {
@@ -845,6 +856,7 @@ public Builder setListWithListAndOtherModelValues(@Nullable List<List<User>> val
             return this;
         }
 
+        @NonNull
         public Builder setListWithMapAndOtherModelValues(@Nullable List<Map<String, User>> value) {
             this.listWithMapAndOtherModelValues = value;
             if (this._bits.length > LIST_WITH_MAP_AND_OTHER_MODEL_VALUES_INDEX) {
@@ -853,6 +865,7 @@ public Builder setListWithMapAndOtherModelValues(@Nullable List<Map<String, User
             return this;
         }
 
+        @NonNull
         public Builder setListWithObjectValues(@Nullable List<String> value) {
             this.listWithObjectValues = value;
             if (this._bits.length > LIST_WITH_OBJECT_VALUES_INDEX) {
@@ -861,6 +874,7 @@ public Builder setListWithObjectValues(@Nullable List<String> value) {
             return this;
         }
 
+        @NonNull
         public Builder setListWithOtherModelValues(@Nullable List<User> value) {
             this.listWithOtherModelValues = value;
             if (this._bits.length > LIST_WITH_OTHER_MODEL_VALUES_INDEX) {
@@ -869,6 +883,7 @@ public Builder setListWithOtherModelValues(@Nullable List<User> value) {
             return this;
         }
 
+        @NonNull
         public Builder setListWithPrimitiveValues(@Nullable List<Integer> value) {
             this.listWithPrimitiveValues = value;
             if (this._bits.length > LIST_WITH_PRIMITIVE_VALUES_INDEX) {
@@ -877,6 +892,7 @@ public Builder setListWithPrimitiveValues(@Nullable List<Integer> value) {
             return this;
         }
 
+        @NonNull
         public Builder setMapPolymorphicValues(@Nullable Map<String, EverythingMapPolymorphicValues> value) {
             this.mapPolymorphicValues = value;
             if (this._bits.length > MAP_POLYMORPHIC_VALUES_INDEX) {
@@ -885,6 +901,7 @@ public Builder setMapPolymorphicValues(@Nullable Map<String, EverythingMapPolymo
             return this;
         }
 
+        @NonNull
         public Builder setMapProp(@Nullable Map<String, Object> value) {
             this.mapProp = value;
             if (this._bits.length > MAP_PROP_INDEX) {
@@ -893,6 +910,7 @@ public Builder setMapProp(@Nullable Map<String, Object> value) {
             return this;
         }
 
+        @NonNull
         public Builder setMapWithListAndOtherModelValues(@Nullable Map<String, List<User>> value) {
             this.mapWithListAndOtherModelValues = value;
             if (this._bits.length > MAP_WITH_LIST_AND_OTHER_MODEL_VALUES_INDEX) {
@@ -901,6 +919,7 @@ public Builder setMapWithListAndOtherModelValues(@Nullable Map<String, List<User
             return this;
         }
 
+        @NonNull
         public Builder setMapWithMapAndOtherModelValues(@Nullable Map<String, Map<String, Object>> value) {
             this.mapWithMapAndOtherModelValues = value;
             if (this._bits.length > MAP_WITH_MAP_AND_OTHER_MODEL_VALUES_INDEX) {
@@ -909,6 +928,7 @@ public Builder setMapWithMapAndOtherModelValues(@Nullable Map<String, Map<String
             return this;
         }
 
+        @NonNull
         public Builder setMapWithObjectValues(@Nullable Map<String, String> value) {
             this.mapWithObjectValues = value;
             if (this._bits.length > MAP_WITH_OBJECT_VALUES_INDEX) {
@@ -917,6 +937,7 @@ public Builder setMapWithObjectValues(@Nullable Map<String, String> value) {
             return this;
         }
 
+        @NonNull
         public Builder setMapWithOtherModelValues(@Nullable Map<String, User> value) {
             this.mapWithOtherModelValues = value;
             if (this._bits.length > MAP_WITH_OTHER_MODEL_VALUES_INDEX) {
@@ -925,6 +946,7 @@ public Builder setMapWithOtherModelValues(@Nullable Map<String, User> value) {
             return this;
         }
 
+        @NonNull
         public Builder setMapWithPrimitiveValues(@Nullable Map<String, Integer> value) {
             this.mapWithPrimitiveValues = value;
             if (this._bits.length > MAP_WITH_PRIMITIVE_VALUES_INDEX) {
@@ -933,6 +955,7 @@ public Builder setMapWithPrimitiveValues(@Nullable Map<String, Integer> value) {
             return this;
         }
 
+        @NonNull
         public Builder setNsintegerEnum(@Nullable EverythingNsintegerEnum value) {
             this.nsintegerEnum = value;
             if (this._bits.length > NSINTEGER_ENUM_INDEX) {
@@ -941,6 +964,7 @@ public Builder setNsintegerEnum(@Nullable EverythingNsintegerEnum value) {
             return this;
         }
 
+        @NonNull
         public Builder setNsuintegerEnum(@Nullable EverythingNsuintegerEnum value) {
             this.nsuintegerEnum = value;
             if (this._bits.length > NSUINTEGER_ENUM_INDEX) {
@@ -949,6 +973,7 @@ public Builder setNsuintegerEnum(@Nullable EverythingNsuintegerEnum value) {
             return this;
         }
 
+        @NonNull
         public Builder setNumberProp(@Nullable Double value) {
             this.numberProp = value;
             if (this._bits.length > NUMBER_PROP_INDEX) {
@@ -957,6 +982,7 @@ public Builder setNumberProp(@Nullable Double value) {
             return this;
         }
 
+        @NonNull
         public Builder setOtherModelProp(@Nullable User value) {
             this.otherModelProp = value;
             if (this._bits.length > OTHER_MODEL_PROP_INDEX) {
@@ -965,6 +991,7 @@ public Builder setOtherModelProp(@Nullable User value) {
             return this;
         }
 
+        @NonNull
         public Builder setPolymorphicProp(@Nullable EverythingPolymorphicProp value) {
             this.polymorphicProp = value;
             if (this._bits.length > POLYMORPHIC_PROP_INDEX) {
@@ -973,6 +1000,7 @@ public Builder setPolymorphicProp(@Nullable EverythingPolymorphicProp value) {
             return this;
         }
 
+        @NonNull
         public Builder setSetProp(@Nullable Set<Object> value) {
             this.setProp = value;
             if (this._bits.length > SET_PROP_INDEX) {
@@ -981,6 +1009,7 @@ public Builder setSetProp(@Nullable Set<Object> value) {
             return this;
         }
 
+        @NonNull
         public Builder setSetPropWithOtherModelValues(@Nullable Set<User> value) {
             this.setPropWithOtherModelValues = value;
             if (this._bits.length > SET_PROP_WITH_OTHER_MODEL_VALUES_INDEX) {
@@ -989,6 +1018,7 @@ public Builder setSetPropWithOtherModelValues(@Nullable Set<User> value) {
             return this;
         }
 
+        @NonNull
         public Builder setSetPropWithPrimitiveValues(@Nullable Set<Integer> value) {
             this.setPropWithPrimitiveValues = value;
             if (this._bits.length > SET_PROP_WITH_PRIMITIVE_VALUES_INDEX) {
@@ -997,6 +1027,7 @@ public Builder setSetPropWithPrimitiveValues(@Nullable Set<Integer> value) {
             return this;
         }
 
+        @NonNull
         public Builder setSetPropWithValues(@Nullable Set<String> value) {
             this.setPropWithValues = value;
             if (this._bits.length > SET_PROP_WITH_VALUES_INDEX) {
@@ -1005,6 +1036,7 @@ public Builder setSetPropWithValues(@Nullable Set<String> value) {
             return this;
         }
 
+        @NonNull
         public Builder setShortEnum(@Nullable EverythingShortEnum value) {
             this.shortEnum = value;
             if (this._bits.length > SHORT_ENUM_INDEX) {
@@ -1013,6 +1045,7 @@ public Builder setShortEnum(@Nullable EverythingShortEnum value) {
             return this;
         }
 
+        @NonNull
         public Builder setStringEnum(@Nullable EverythingStringEnum value) {
             this.stringEnum = value;
             if (this._bits.length > STRING_ENUM_INDEX) {
@@ -1021,6 +1054,7 @@ public Builder setStringEnum(@Nullable EverythingStringEnum value) {
             return this;
         }
 
+        @NonNull
         public Builder setStringProp(@Nullable String value) {
             this.stringProp = value;
             if (this._bits.length > STRING_PROP_INDEX) {
@@ -1029,6 +1063,7 @@ public Builder setStringProp(@Nullable String value) {
             return this;
         }
 
+        @NonNull
         public Builder setType(@Nullable String value) {
             this.type = value;
             if (this._bits.length > TYPE_INDEX) {
@@ -1037,6 +1072,7 @@ public Builder setType(@Nullable String value) {
             return this;
         }
 
+        @NonNull
         public Builder setUnsignedCharEnum(@Nullable EverythingUnsignedCharEnum value) {
             this.unsignedCharEnum = value;
             if (this._bits.length > UNSIGNED_CHAR_ENUM_INDEX) {
@@ -1045,6 +1081,7 @@ public Builder setUnsignedCharEnum(@Nullable EverythingUnsignedCharEnum value) {
             return this;
         }
 
+        @NonNull
         public Builder setUnsignedIntEnum(@Nullable EverythingUnsignedIntEnum value) {
             this.unsignedIntEnum = value;
             if (this._bits.length > UNSIGNED_INT_ENUM_INDEX) {
@@ -1053,6 +1090,7 @@ public Builder setUnsignedIntEnum(@Nullable EverythingUnsignedIntEnum value) {
             return this;
         }
 
+        @NonNull
         public Builder setUnsignedShortEnum(@Nullable EverythingUnsignedShortEnum value) {
             this.unsignedShortEnum = value;
             if (this._bits.length > UNSIGNED_SHORT_ENUM_INDEX) {
@@ -1061,6 +1099,7 @@ public Builder setUnsignedShortEnum(@Nullable EverythingUnsignedShortEnum value)
             return this;
         }
 
+        @NonNull
         public Builder setUriProp(@Nullable String value) {
             this.uriProp = value;
             if (this._bits.length > URI_PROP_INDEX) {
@@ -1256,7 +1295,7 @@ public Everything build() {
             );
         }
 
-        public void mergeFrom(Everything model) {
+        public void mergeFrom(@NonNull Everything model) {
             if (model.getArrayPropIsSet()) {
                 this.arrayProp = model.arrayProp;
                 if (this._bits.length > ARRAY_PROP_INDEX) {
@@ -1478,8 +1517,9 @@ public void mergeFrom(Everything model) {
 
     public static class EverythingTypeAdapterFactory implements TypeAdapterFactory {
 
+        @Nullable
         @Override
-        public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) {
+        public <T> TypeAdapter<T> create(@NonNull Gson gson, @NonNull TypeToken<T> typeToken) {
             if (!Everything.class.isAssignableFrom(typeToken.getRawType())) {
                 return null;
             }
@@ -1528,14 +1568,14 @@ public static class EverythingTypeAdapter extends TypeAdapter<Everything> {
         private TypeAdapter<String> stringTypeAdapter;
         private TypeAdapter<User> userTypeAdapter;
 
-        public EverythingTypeAdapter(Gson gson, EverythingTypeAdapterFactory factory, TypeToken typeToken) {
+        public EverythingTypeAdapter(@NonNull Gson gson, EverythingTypeAdapterFactory factory, TypeToken typeToken) {
             this.factory = factory;
             this.gson = gson;
             this.typeToken = typeToken;
         }
 
         @Override
-        public void write(JsonWriter writer, Everything value) throws IOException {
+        public void write(@NonNull JsonWriter writer, Everything value) throws IOException {
             if (this.delegateTypeAdapter == null) {
                 this.delegateTypeAdapter = this.gson.getDelegateAdapter(this.factory, this.typeToken);
             }
@@ -1543,8 +1583,9 @@ public void write(JsonWriter writer, Everything value) throws IOException {
             this.delegateTypeAdapter.write(writer, value);
         }
 
+        @Nullable
         @Override
-        public Everything read(JsonReader reader) throws IOException {
+        public Everything read(@NonNull JsonReader reader) throws IOException {
             if (reader.peek() == JsonToken.NULL) {
                 reader.nextNull();
                 return null;
diff --git a/Examples/Java/Sources/Image.java b/Examples/Java/Sources/Image.java
index 06b8111a..d2b65ce4 100644
--- a/Examples/Java/Sources/Image.java
+++ b/Examples/Java/Sources/Image.java
@@ -54,15 +54,18 @@ private Image(
         this._bits = _bits;
     }
 
+    @NonNull
     public static Image.Builder builder() {
         return new Image.Builder();
     }
 
+    @NonNull
     public Image.Builder toBuilder() {
         return new Image.Builder(this);
     }
 
-    public Image mergeFrom(Image model) {
+    @NonNull
+    public Image mergeFrom(@NonNull Image model) {
         Image.Builder builder = this.toBuilder();
         builder.mergeFrom(model);
         return builder.build();
@@ -133,6 +136,7 @@ private Builder(@NonNull Image model) {
             this._bits = model._bits;
         }
 
+        @NonNull
         public Builder setHeight(@Nullable Integer value) {
             this.height = value;
             if (this._bits.length > HEIGHT_INDEX) {
@@ -141,6 +145,7 @@ public Builder setHeight(@Nullable Integer value) {
             return this;
         }
 
+        @NonNull
         public Builder setUrl(@Nullable String value) {
             this.url = value;
             if (this._bits.length > URL_INDEX) {
@@ -149,6 +154,7 @@ public Builder setUrl(@Nullable String value) {
             return this;
         }
 
+        @NonNull
         public Builder setWidth(@Nullable Integer value) {
             this.width = value;
             if (this._bits.length > WIDTH_INDEX) {
@@ -179,7 +185,7 @@ public Image build() {
             );
         }
 
-        public void mergeFrom(Image model) {
+        public void mergeFrom(@NonNull Image model) {
             if (model.getHeightIsSet()) {
                 this.height = model.height;
                 if (this._bits.length > HEIGHT_INDEX) {
@@ -203,8 +209,9 @@ public void mergeFrom(Image model) {
 
     public static class ImageTypeAdapterFactory implements TypeAdapterFactory {
 
+        @Nullable
         @Override
-        public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) {
+        public <T> TypeAdapter<T> create(@NonNull Gson gson, @NonNull TypeToken<T> typeToken) {
             if (!Image.class.isAssignableFrom(typeToken.getRawType())) {
                 return null;
             }
@@ -222,14 +229,14 @@ public static class ImageTypeAdapter extends TypeAdapter<Image> {
         private TypeAdapter<Integer> integerTypeAdapter;
         private TypeAdapter<String> stringTypeAdapter;
 
-        public ImageTypeAdapter(Gson gson, ImageTypeAdapterFactory factory, TypeToken typeToken) {
+        public ImageTypeAdapter(@NonNull Gson gson, ImageTypeAdapterFactory factory, TypeToken typeToken) {
             this.factory = factory;
             this.gson = gson;
             this.typeToken = typeToken;
         }
 
         @Override
-        public void write(JsonWriter writer, Image value) throws IOException {
+        public void write(@NonNull JsonWriter writer, Image value) throws IOException {
             if (this.delegateTypeAdapter == null) {
                 this.delegateTypeAdapter = this.gson.getDelegateAdapter(this.factory, this.typeToken);
             }
@@ -237,8 +244,9 @@ public void write(JsonWriter writer, Image value) throws IOException {
             this.delegateTypeAdapter.write(writer, value);
         }
 
+        @Nullable
         @Override
-        public Image read(JsonReader reader) throws IOException {
+        public Image read(@NonNull JsonReader reader) throws IOException {
             if (reader.peek() == JsonToken.NULL) {
                 reader.nextNull();
                 return null;
diff --git a/Examples/Java/Sources/Model.java b/Examples/Java/Sources/Model.java
index fa9ffe8e..f0dc0fa8 100644
--- a/Examples/Java/Sources/Model.java
+++ b/Examples/Java/Sources/Model.java
@@ -46,15 +46,18 @@ private Model(
         this._bits = _bits;
     }
 
+    @NonNull
     public static Model.Builder builder() {
         return new Model.Builder();
     }
 
+    @NonNull
     public Model.Builder toBuilder() {
         return new Model.Builder(this);
     }
 
-    public Model mergeFrom(Model model) {
+    @NonNull
+    public Model mergeFrom(@NonNull Model model) {
         Model.Builder builder = this.toBuilder();
         builder.mergeFrom(model);
         return builder.build();
@@ -99,6 +102,7 @@ private Builder(@NonNull Model model) {
             this._bits = model._bits;
         }
 
+        @NonNull
         public Builder setUid(@Nullable String value) {
             this.uid = value;
             if (this._bits.length > ID_INDEX) {
@@ -119,7 +123,7 @@ public Model build() {
             );
         }
 
-        public void mergeFrom(Model model) {
+        public void mergeFrom(@NonNull Model model) {
             if (model.getUidIsSet()) {
                 this.uid = model.uid;
                 if (this._bits.length > ID_INDEX) {
@@ -131,8 +135,9 @@ public void mergeFrom(Model model) {
 
     public static class ModelTypeAdapterFactory implements TypeAdapterFactory {
 
+        @Nullable
         @Override
-        public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) {
+        public <T> TypeAdapter<T> create(@NonNull Gson gson, @NonNull TypeToken<T> typeToken) {
             if (!Model.class.isAssignableFrom(typeToken.getRawType())) {
                 return null;
             }
@@ -149,14 +154,14 @@ public static class ModelTypeAdapter extends TypeAdapter<Model> {
 
         private TypeAdapter<String> stringTypeAdapter;
 
-        public ModelTypeAdapter(Gson gson, ModelTypeAdapterFactory factory, TypeToken typeToken) {
+        public ModelTypeAdapter(@NonNull Gson gson, ModelTypeAdapterFactory factory, TypeToken typeToken) {
             this.factory = factory;
             this.gson = gson;
             this.typeToken = typeToken;
         }
 
         @Override
-        public void write(JsonWriter writer, Model value) throws IOException {
+        public void write(@NonNull JsonWriter writer, Model value) throws IOException {
             if (this.delegateTypeAdapter == null) {
                 this.delegateTypeAdapter = this.gson.getDelegateAdapter(this.factory, this.typeToken);
             }
@@ -164,8 +169,9 @@ public void write(JsonWriter writer, Model value) throws IOException {
             this.delegateTypeAdapter.write(writer, value);
         }
 
+        @Nullable
         @Override
-        public Model read(JsonReader reader) throws IOException {
+        public Model read(@NonNull JsonReader reader) throws IOException {
             if (reader.peek() == JsonToken.NULL) {
                 reader.nextNull();
                 return null;
diff --git a/Examples/Java/Sources/Pin.java b/Examples/Java/Sources/Pin.java
index 0190166f..b273b4e6 100644
--- a/Examples/Java/Sources/Pin.java
+++ b/Examples/Java/Sources/Pin.java
@@ -128,15 +128,18 @@ private Pin(
         this._bits = _bits;
     }
 
+    @NonNull
     public static Pin.Builder builder() {
         return new Pin.Builder();
     }
 
+    @NonNull
     public Pin.Builder toBuilder() {
         return new Pin.Builder(this);
     }
 
-    public Pin mergeFrom(Pin model) {
+    @NonNull
+    public Pin mergeFrom(@NonNull Pin model) {
         Pin.Builder builder = this.toBuilder();
         builder.mergeFrom(model);
         return builder.build();
@@ -373,6 +376,7 @@ private Builder(@NonNull Pin model) {
             this._bits = model._bits;
         }
 
+        @NonNull
         public Builder setAttribution(@Nullable Map<String, String> value) {
             this.attribution = value;
             if (this._bits.length > ATTRIBUTION_INDEX) {
@@ -381,6 +385,7 @@ public Builder setAttribution(@Nullable Map<String, String> value) {
             return this;
         }
 
+        @NonNull
         public Builder setAttributionObjects(@Nullable List<PinAttributionObjects> value) {
             this.attributionObjects = value;
             if (this._bits.length > ATTRIBUTION_OBJECTS_INDEX) {
@@ -389,6 +394,7 @@ public Builder setAttributionObjects(@Nullable List<PinAttributionObjects> value
             return this;
         }
 
+        @NonNull
         public Builder setBoard(@Nullable Board value) {
             this.board = value;
             if (this._bits.length > BOARD_INDEX) {
@@ -397,6 +403,7 @@ public Builder setBoard(@Nullable Board value) {
             return this;
         }
 
+        @NonNull
         public Builder setColor(@Nullable String value) {
             this.color = value;
             if (this._bits.length > COLOR_INDEX) {
@@ -405,6 +412,7 @@ public Builder setColor(@Nullable String value) {
             return this;
         }
 
+        @NonNull
         public Builder setCounts(@Nullable Map<String, Integer> value) {
             this.counts = value;
             if (this._bits.length > COUNTS_INDEX) {
@@ -413,6 +421,7 @@ public Builder setCounts(@Nullable Map<String, Integer> value) {
             return this;
         }
 
+        @NonNull
         public Builder setCreatedAt(@NonNull Date value) {
             this.createdAt = value;
             if (this._bits.length > CREATED_AT_INDEX) {
@@ -421,6 +430,7 @@ public Builder setCreatedAt(@NonNull Date value) {
             return this;
         }
 
+        @NonNull
         public Builder setCreator(@NonNull Map<String, User> value) {
             this.creator = value;
             if (this._bits.length > CREATOR_INDEX) {
@@ -429,6 +439,7 @@ public Builder setCreator(@NonNull Map<String, User> value) {
             return this;
         }
 
+        @NonNull
         public Builder setDescription(@Nullable String value) {
             this.description = value;
             if (this._bits.length > DESCRIPTION_INDEX) {
@@ -437,6 +448,7 @@ public Builder setDescription(@Nullable String value) {
             return this;
         }
 
+        @NonNull
         public Builder setUid(@NonNull String value) {
             this.uid = value;
             if (this._bits.length > ID_INDEX) {
@@ -445,6 +457,7 @@ public Builder setUid(@NonNull String value) {
             return this;
         }
 
+        @NonNull
         public Builder setImage(@Nullable Image value) {
             this.image = value;
             if (this._bits.length > IMAGE_INDEX) {
@@ -453,6 +466,7 @@ public Builder setImage(@Nullable Image value) {
             return this;
         }
 
+        @NonNull
         public Builder setInStock(@Nullable PinInStock value) {
             this.inStock = value;
             if (this._bits.length > IN_STOCK_INDEX) {
@@ -461,6 +475,7 @@ public Builder setInStock(@Nullable PinInStock value) {
             return this;
         }
 
+        @NonNull
         public Builder setLink(@Nullable String value) {
             this.link = value;
             if (this._bits.length > LINK_INDEX) {
@@ -469,6 +484,7 @@ public Builder setLink(@Nullable String value) {
             return this;
         }
 
+        @NonNull
         public Builder setMedia(@Nullable Map<String, String> value) {
             this.media = value;
             if (this._bits.length > MEDIA_INDEX) {
@@ -477,6 +493,7 @@ public Builder setMedia(@Nullable Map<String, String> value) {
             return this;
         }
 
+        @NonNull
         public Builder setNote(@Nullable String value) {
             this.note = value;
             if (this._bits.length > NOTE_INDEX) {
@@ -485,6 +502,7 @@ public Builder setNote(@Nullable String value) {
             return this;
         }
 
+        @NonNull
         public Builder setTags(@Nullable List<Map<String, Object>> value) {
             this.tags = value;
             if (this._bits.length > TAGS_INDEX) {
@@ -493,6 +511,7 @@ public Builder setTags(@Nullable List<Map<String, Object>> value) {
             return this;
         }
 
+        @NonNull
         public Builder setUrl(@Nullable String value) {
             this.url = value;
             if (this._bits.length > URL_INDEX) {
@@ -501,6 +520,7 @@ public Builder setUrl(@Nullable String value) {
             return this;
         }
 
+        @NonNull
         public Builder setVisualSearchAttrs(@Nullable Map<String, Object> value) {
             this.visualSearchAttrs = value;
             if (this._bits.length > VISUAL_SEARCH_ATTRS_INDEX) {
@@ -601,7 +621,7 @@ public Pin build() {
             );
         }
 
-        public void mergeFrom(Pin model) {
+        public void mergeFrom(@NonNull Pin model) {
             if (model.getAttributionIsSet()) {
                 this.attribution = model.attribution;
                 if (this._bits.length > ATTRIBUTION_INDEX) {
@@ -709,8 +729,9 @@ public void mergeFrom(Pin model) {
 
     public static class PinTypeAdapterFactory implements TypeAdapterFactory {
 
+        @Nullable
         @Override
-        public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) {
+        public <T> TypeAdapter<T> create(@NonNull Gson gson, @NonNull TypeToken<T> typeToken) {
             if (!Pin.class.isAssignableFrom(typeToken.getRawType())) {
                 return null;
             }
@@ -737,14 +758,14 @@ public static class PinTypeAdapter extends TypeAdapter<Pin> {
         private TypeAdapter<PinInStock> pinInStockTypeAdapter;
         private TypeAdapter<String> stringTypeAdapter;
 
-        public PinTypeAdapter(Gson gson, PinTypeAdapterFactory factory, TypeToken typeToken) {
+        public PinTypeAdapter(@NonNull Gson gson, PinTypeAdapterFactory factory, TypeToken typeToken) {
             this.factory = factory;
             this.gson = gson;
             this.typeToken = typeToken;
         }
 
         @Override
-        public void write(JsonWriter writer, Pin value) throws IOException {
+        public void write(@NonNull JsonWriter writer, Pin value) throws IOException {
             if (this.delegateTypeAdapter == null) {
                 this.delegateTypeAdapter = this.gson.getDelegateAdapter(this.factory, this.typeToken);
             }
@@ -752,8 +773,9 @@ public void write(JsonWriter writer, Pin value) throws IOException {
             this.delegateTypeAdapter.write(writer, value);
         }
 
+        @Nullable
         @Override
-        public Pin read(JsonReader reader) throws IOException {
+        public Pin read(@NonNull JsonReader reader) throws IOException {
             if (reader.peek() == JsonToken.NULL) {
                 reader.nextNull();
                 return null;
diff --git a/Examples/Java/Sources/User.java b/Examples/Java/Sources/User.java
index baa5eca5..5eb28fe7 100644
--- a/Examples/Java/Sources/User.java
+++ b/Examples/Java/Sources/User.java
@@ -86,15 +86,18 @@ private User(
         this._bits = _bits;
     }
 
+    @NonNull
     public static User.Builder builder() {
         return new User.Builder();
     }
 
+    @NonNull
     public User.Builder toBuilder() {
         return new User.Builder(this);
     }
 
-    public User mergeFrom(User model) {
+    @NonNull
+    public User mergeFrom(@NonNull User model) {
         User.Builder builder = this.toBuilder();
         builder.mergeFrom(model);
         return builder.build();
@@ -247,6 +250,7 @@ private Builder(@NonNull User model) {
             this._bits = model._bits;
         }
 
+        @NonNull
         public Builder setBio(@Nullable String value) {
             this.bio = value;
             if (this._bits.length > BIO_INDEX) {
@@ -255,6 +259,7 @@ public Builder setBio(@Nullable String value) {
             return this;
         }
 
+        @NonNull
         public Builder setCounts(@Nullable Map<String, Integer> value) {
             this.counts = value;
             if (this._bits.length > COUNTS_INDEX) {
@@ -263,6 +268,7 @@ public Builder setCounts(@Nullable Map<String, Integer> value) {
             return this;
         }
 
+        @NonNull
         public Builder setCreatedAt(@Nullable Date value) {
             this.createdAt = value;
             if (this._bits.length > CREATED_AT_INDEX) {
@@ -271,6 +277,7 @@ public Builder setCreatedAt(@Nullable Date value) {
             return this;
         }
 
+        @NonNull
         public Builder setEmailFrequency(@Nullable UserEmailFrequency value) {
             this.emailFrequency = value;
             if (this._bits.length > EMAIL_FREQUENCY_INDEX) {
@@ -279,6 +286,7 @@ public Builder setEmailFrequency(@Nullable UserEmailFrequency value) {
             return this;
         }
 
+        @NonNull
         public Builder setFirstName(@Nullable String value) {
             this.firstName = value;
             if (this._bits.length > FIRST_NAME_INDEX) {
@@ -287,6 +295,7 @@ public Builder setFirstName(@Nullable String value) {
             return this;
         }
 
+        @NonNull
         public Builder setUid(@Nullable String value) {
             this.uid = value;
             if (this._bits.length > ID_INDEX) {
@@ -295,6 +304,7 @@ public Builder setUid(@Nullable String value) {
             return this;
         }
 
+        @NonNull
         public Builder setImage(@Nullable Image value) {
             this.image = value;
             if (this._bits.length > IMAGE_INDEX) {
@@ -303,6 +313,7 @@ public Builder setImage(@Nullable Image value) {
             return this;
         }
 
+        @NonNull
         public Builder setLastName(@Nullable String value) {
             this.lastName = value;
             if (this._bits.length > LAST_NAME_INDEX) {
@@ -311,6 +322,7 @@ public Builder setLastName(@Nullable String value) {
             return this;
         }
 
+        @NonNull
         public Builder setType(@Nullable String value) {
             this.type = value;
             if (this._bits.length > TYPE_INDEX) {
@@ -319,6 +331,7 @@ public Builder setType(@Nullable String value) {
             return this;
         }
 
+        @NonNull
         public Builder setUsername(@Nullable String value) {
             this.username = value;
             if (this._bits.length > USERNAME_INDEX) {
@@ -384,7 +397,7 @@ public User build() {
             );
         }
 
-        public void mergeFrom(User model) {
+        public void mergeFrom(@NonNull User model) {
             if (model.getBioIsSet()) {
                 this.bio = model.bio;
                 if (this._bits.length > BIO_INDEX) {
@@ -450,8 +463,9 @@ public void mergeFrom(User model) {
 
     public static class UserTypeAdapterFactory implements TypeAdapterFactory {
 
+        @Nullable
         @Override
-        public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) {
+        public <T> TypeAdapter<T> create(@NonNull Gson gson, @NonNull TypeToken<T> typeToken) {
             if (!User.class.isAssignableFrom(typeToken.getRawType())) {
                 return null;
             }
@@ -472,14 +486,14 @@ public static class UserTypeAdapter extends TypeAdapter<User> {
         private TypeAdapter<String> stringTypeAdapter;
         private TypeAdapter<UserEmailFrequency> userEmailFrequencyTypeAdapter;
 
-        public UserTypeAdapter(Gson gson, UserTypeAdapterFactory factory, TypeToken typeToken) {
+        public UserTypeAdapter(@NonNull Gson gson, UserTypeAdapterFactory factory, TypeToken typeToken) {
             this.factory = factory;
             this.gson = gson;
             this.typeToken = typeToken;
         }
 
         @Override
-        public void write(JsonWriter writer, User value) throws IOException {
+        public void write(@NonNull JsonWriter writer, User value) throws IOException {
             if (this.delegateTypeAdapter == null) {
                 this.delegateTypeAdapter = this.gson.getDelegateAdapter(this.factory, this.typeToken);
             }
@@ -487,8 +501,9 @@ public void write(JsonWriter writer, User value) throws IOException {
             this.delegateTypeAdapter.write(writer, value);
         }
 
+        @Nullable
         @Override
-        public User read(JsonReader reader) throws IOException {
+        public User read(@NonNull JsonReader reader) throws IOException {
             if (reader.peek() == JsonToken.NULL) {
                 reader.nextNull();
                 return null;
diff --git a/Examples/Java/Sources/VariableSubtitution.java b/Examples/Java/Sources/VariableSubtitution.java
index a2ab01eb..30e8d311 100644
--- a/Examples/Java/Sources/VariableSubtitution.java
+++ b/Examples/Java/Sources/VariableSubtitution.java
@@ -58,15 +58,18 @@ private VariableSubtitution(
         this._bits = _bits;
     }
 
+    @NonNull
     public static VariableSubtitution.Builder builder() {
         return new VariableSubtitution.Builder();
     }
 
+    @NonNull
     public VariableSubtitution.Builder toBuilder() {
         return new VariableSubtitution.Builder(this);
     }
 
-    public VariableSubtitution mergeFrom(VariableSubtitution model) {
+    @NonNull
+    public VariableSubtitution mergeFrom(@NonNull VariableSubtitution model) {
         VariableSubtitution.Builder builder = this.toBuilder();
         builder.mergeFrom(model);
         return builder.build();
@@ -151,6 +154,7 @@ private Builder(@NonNull VariableSubtitution model) {
             this._bits = model._bits;
         }
 
+        @NonNull
         public Builder setAllocProp(@Nullable Integer value) {
             this.allocProp = value;
             if (this._bits.length > ALLOC_PROP_INDEX) {
@@ -159,6 +163,7 @@ public Builder setAllocProp(@Nullable Integer value) {
             return this;
         }
 
+        @NonNull
         public Builder setCopyProp(@Nullable Integer value) {
             this.copyProp = value;
             if (this._bits.length > COPY_PROP_INDEX) {
@@ -167,6 +172,7 @@ public Builder setCopyProp(@Nullable Integer value) {
             return this;
         }
 
+        @NonNull
         public Builder setMutableCopyProp(@Nullable Integer value) {
             this.mutableCopyProp = value;
             if (this._bits.length > MUTABLE_COPY_PROP_INDEX) {
@@ -175,6 +181,7 @@ public Builder setMutableCopyProp(@Nullable Integer value) {
             return this;
         }
 
+        @NonNull
         public Builder setNewProp(@Nullable Integer value) {
             this.newProp = value;
             if (this._bits.length > NEW_PROP_INDEX) {
@@ -210,7 +217,7 @@ public VariableSubtitution build() {
             );
         }
 
-        public void mergeFrom(VariableSubtitution model) {
+        public void mergeFrom(@NonNull VariableSubtitution model) {
             if (model.getAllocPropIsSet()) {
                 this.allocProp = model.allocProp;
                 if (this._bits.length > ALLOC_PROP_INDEX) {
@@ -240,8 +247,9 @@ public void mergeFrom(VariableSubtitution model) {
 
     public static class VariableSubtitutionTypeAdapterFactory implements TypeAdapterFactory {
 
+        @Nullable
         @Override
-        public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) {
+        public <T> TypeAdapter<T> create(@NonNull Gson gson, @NonNull TypeToken<T> typeToken) {
             if (!VariableSubtitution.class.isAssignableFrom(typeToken.getRawType())) {
                 return null;
             }
@@ -258,14 +266,14 @@ public static class VariableSubtitutionTypeAdapter extends TypeAdapter<VariableS
 
         private TypeAdapter<Integer> integerTypeAdapter;
 
-        public VariableSubtitutionTypeAdapter(Gson gson, VariableSubtitutionTypeAdapterFactory factory, TypeToken typeToken) {
+        public VariableSubtitutionTypeAdapter(@NonNull Gson gson, VariableSubtitutionTypeAdapterFactory factory, TypeToken typeToken) {
             this.factory = factory;
             this.gson = gson;
             this.typeToken = typeToken;
         }
 
         @Override
-        public void write(JsonWriter writer, VariableSubtitution value) throws IOException {
+        public void write(@NonNull JsonWriter writer, VariableSubtitution value) throws IOException {
             if (this.delegateTypeAdapter == null) {
                 this.delegateTypeAdapter = this.gson.getDelegateAdapter(this.factory, this.typeToken);
             }
@@ -273,8 +281,9 @@ public void write(JsonWriter writer, VariableSubtitution value) throws IOExcepti
             this.delegateTypeAdapter.write(writer, value);
         }
 
+        @Nullable
         @Override
-        public VariableSubtitution read(JsonReader reader) throws IOException {
+        public VariableSubtitution read(@NonNull JsonReader reader) throws IOException {
             if (reader.peek() == JsonToken.NULL) {
                 reader.nextNull();
                 return null;
diff --git a/Sources/Core/JavaIR.swift b/Sources/Core/JavaIR.swift
index 9f1cc9fe..9374ae59 100644
--- a/Sources/Core/JavaIR.swift
+++ b/Sources/Core/JavaIR.swift
@@ -207,7 +207,7 @@ public struct JavaIR {
 
         func render() -> [String] {
             // HACK: We should actually have an enum / optionset that we can check for abstract, static, ...
-            let annotationLines = annotations.map { "@\($0.rendered)" }
+            let annotationLines = annotations.map { "@\($0.rendered)" }.sorted()
 
             let throwsString = throwableExceptions.isEmpty ? "" : " throws " + throwableExceptions.joined(separator: ", ")
 
@@ -359,7 +359,7 @@ public struct JavaIR {
 
             let extendsStmt = extends.map { " extends \($0) " } ?? ""
 
-            var lines = annotations.map { "@\($0.rendered)" } + [
+            var lines = annotations.map { "@\($0.rendered)" }.sorted() + [
                 "\(modifiers.render()) class \(name)\(extendsStmt)\(implementsStmt) {",
             ]
 
diff --git a/Sources/Core/JavaModelRenderer.swift b/Sources/Core/JavaModelRenderer.swift
index 16dcbc1b..af45db76 100644
--- a/Sources/Core/JavaModelRenderer.swift
+++ b/Sources/Core/JavaModelRenderer.swift
@@ -157,7 +157,7 @@ public struct JavaModelRenderer: JavaFileRenderer {
 
     func renderModelMergeFrom() -> JavaIR.Method {
         let methodName = "mergeFrom"
-        return JavaIR.method(annotations: decorations.annotationsForMethod(methodName), [.public], className + " " + methodName + "(" + className + " model)") { [
+        return JavaIR.method(annotations: decorations.annotationsForMethod(methodName).union([.nonnull]), [.public], className + " " + methodName + "(@NonNull " + className + " model)") { [
             self.className + ".Builder builder = this.toBuilder();",
             "builder.mergeFrom(model);",
             "return builder.build();",
@@ -166,11 +166,11 @@ public struct JavaModelRenderer: JavaFileRenderer {
 
     func renderModelToBuilder() -> JavaIR.Method {
         let methodName = "toBuilder"
-        return JavaIR.method(annotations: decorations.annotationsForMethod(methodName), [.public], className + ".Builder " + methodName + "()") { ["return new " + self.className + ".Builder(this);"] }
+        return JavaIR.method(annotations: decorations.annotationsForMethod(methodName).union([.nonnull]), [.public], className + ".Builder " + methodName + "()") { ["return new " + self.className + ".Builder(this);"] }
     }
 
     func renderModelBuilder() -> JavaIR.Method {
-        return JavaIR.method([.public, .static], className + ".Builder builder()") { [
+        return JavaIR.method(annotations: [.nonnull], [.public, .static], className + ".Builder builder()") { [
             "return new \(className).Builder();",
         ] }
     }
@@ -207,7 +207,7 @@ public struct JavaModelRenderer: JavaFileRenderer {
 
     func renderBuilderSetters(modifiers: JavaModifier = [.public]) -> [JavaIR.Method] {
         let setters = transitiveProperties.map { param, schemaObj in
-            JavaIR.method(modifiers, "Builder set\(Languages.java.snakeCaseToCapitalizedPropertyName(param))(\(self.typeFromSchema(param, schemaObj)) value)") { [
+            JavaIR.method(annotations: [.nonnull], modifiers, "Builder set\(Languages.java.snakeCaseToCapitalizedPropertyName(param))(\(self.typeFromSchema(param, schemaObj)) value)") { [
                 "this." + Languages.java.snakeCaseToPropertyName(param) + " = value;",
                 JavaIR.ifBlock(condition: "this._bits.length > " + param.uppercased() + "_INDEX") { [
                     "this._bits[" + param.uppercased() + "_INDEX] = true;",
@@ -227,7 +227,7 @@ public struct JavaModelRenderer: JavaFileRenderer {
                 ] },
             ] }
         })
-        return JavaIR.method([.public], "void mergeFrom(" + className + " model)") { body }
+        return JavaIR.method([.public], "void mergeFrom(@NonNull " + className + " model)") { body }
     }
 
     func renderBuilderProperties(modifiers _: JavaModifier = [.private]) -> [[JavaIR.Property]] {
@@ -243,7 +243,7 @@ public struct JavaModelRenderer: JavaFileRenderer {
     // MARK: - TypeAdapterFactory
 
     func renderTypeAdapterFactoryMethods() -> [JavaIR.Method] {
-        return [JavaIR.method(annotations: [JavaAnnotation.override], [.public], "<T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken)") { [
+        return [JavaIR.method(annotations: [.nullable, JavaAnnotation.override], [.public], "<T> TypeAdapter<T> create(@NonNull Gson gson, @NonNull TypeToken<T> typeToken)") { [
             JavaIR.ifBlock(condition: "!" + className + ".class.isAssignableFrom(typeToken.getRawType())") { [
                 "return null;",
             ] },
@@ -308,7 +308,7 @@ public struct JavaModelRenderer: JavaFileRenderer {
         let constructor = JavaIR.method(
             annotations: [],
             [.public],
-            className + "TypeAdapter(Gson gson, " + className + "TypeAdapterFactory factory, TypeToken typeToken)"
+            className + "TypeAdapter(@NonNull Gson gson, " + className + "TypeAdapterFactory factory, TypeToken typeToken)"
         ) { [
             "this.factory = factory;",
             "this.gson = gson;",
@@ -319,7 +319,7 @@ public struct JavaModelRenderer: JavaFileRenderer {
         let write = JavaIR.methodThatThrows(
             annotations: [JavaAnnotation.override],
             [.public],
-            "void write(JsonWriter writer, " + className + " value)",
+            "void write(@NonNull JsonWriter writer, " + className + " value)",
             ["IOException"]
         ) { [
             JavaIR.ifBlock(condition: "this.delegateTypeAdapter == null") { [
@@ -331,9 +331,9 @@ public struct JavaModelRenderer: JavaFileRenderer {
         }
 
         let read = JavaIR.methodThatThrows(
-            annotations: [JavaAnnotation.override],
+            annotations: [.nullable, JavaAnnotation.override],
             [.public],
-            className + " read(JsonReader reader)",
+            className + " read(@NonNull JsonReader reader)",
             ["IOException"]
         ) { [
             JavaIR.ifBlock(condition: "reader.peek() == JsonToken.NULL") { [