Fix Serde nullability annotations

sdk-api/src/main/java/dev/restate/sdk/AwakeableHandle.java

@@ -9,7 +9,6 @@
 package dev.restate.sdk;
 
 import dev.restate.sdk.common.Serde;
-import org.jspecify.annotations.NonNull;
 
 /** This class represents a handle to an {@link Awakeable} created in another service. */
 public interface AwakeableHandle {
@@ -21,7 +20,7 @@ public interface AwakeableHandle {
    * @param payload the result payload. MUST NOT be null.
    * @see Awakeable
    */
-  <T> void resolve(Serde<T> serde, @NonNull T payload);
+  <T> void resolve(Serde<T> serde, T payload);
 
   /**
    * Complete with failure the {@link Awakeable}.

sdk-api/src/main/java/dev/restate/sdk/JsonSerdes.java

@@ -18,7 +18,7 @@
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import org.jspecify.annotations.Nullable;
+import org.jspecify.annotations.NonNull;
 
 /**
  * Collection of common serializers/deserializers.
@@ -30,7 +30,7 @@ public abstract class JsonSerdes {
   private JsonSerdes() {}
 
   /** {@link Serde} for {@link String}. This writes and reads {@link String} as JSON value. */
-  public static Serde<String> STRING =
+  public static Serde<@NonNull String> STRING =
       usingJackson(
           JsonGenerator::writeString,
           p -> {
@@ -42,7 +42,7 @@ private JsonSerdes() {}
           });
 
   /** {@link Serde} for {@link Boolean}. This writes and reads {@link Boolean} as JSON value. */
-  public static Serde<Boolean> BOOLEAN =
+  public static Serde<@NonNull Boolean> BOOLEAN =
       usingJackson(
           JsonGenerator::writeBoolean,
           p -> {
@@ -51,7 +51,7 @@ private JsonSerdes() {}
           });
 
   /** {@link Serde} for {@link Byte}. This writes and reads {@link Byte} as JSON value. */
-  public static Serde<Byte> BYTE =
+  public static Serde<@NonNull Byte> BYTE =
       usingJackson(
           JsonGenerator::writeNumber,
           p -> {
@@ -60,7 +60,7 @@ private JsonSerdes() {}
           });
 
   /** {@link Serde} for {@link Short}. This writes and reads {@link Short} as JSON value. */
-  public static Serde<Short> SHORT =
+  public static Serde<@NonNull Short> SHORT =
       usingJackson(
           JsonGenerator::writeNumber,
           p -> {
@@ -69,7 +69,7 @@ private JsonSerdes() {}
           });
 
   /** {@link Serde} for {@link Integer}. This writes and reads {@link Integer} as JSON value. */
-  public static Serde<Integer> INT =
+  public static Serde<@NonNull Integer> INT =
       usingJackson(
           JsonGenerator::writeNumber,
           p -> {
@@ -78,7 +78,7 @@ private JsonSerdes() {}
           });
 
   /** {@link Serde} for {@link Long}. This writes and reads {@link Long} as JSON value. */
-  public static Serde<Long> LONG =
+  public static Serde<@NonNull Long> LONG =
       usingJackson(
           JsonGenerator::writeNumber,
           p -> {
@@ -87,7 +87,7 @@ private JsonSerdes() {}
           });
 
   /** {@link Serde} for {@link Float}. This writes and reads {@link Float} as JSON value. */
-  public static Serde<Float> FLOAT =
+  public static Serde<@NonNull Float> FLOAT =
       usingJackson(
           JsonGenerator::writeNumber,
           p -> {
@@ -96,7 +96,7 @@ private JsonSerdes() {}
           });
 
   /** {@link Serde} for {@link Double}. This writes and reads {@link Double} as JSON value. */
-  public static Serde<Double> DOUBLE =
+  public static Serde<@NonNull Double> DOUBLE =
       usingJackson(
           JsonGenerator::writeNumber,
           p -> {
@@ -108,12 +108,12 @@ private JsonSerdes() {}
 
   private static final JsonFactory JSON_FACTORY = new JsonFactory();
 
-  private static <T> Serde<T> usingJackson(
+  private static <T extends @NonNull Object> Serde<T> usingJackson(
       ThrowingBiConsumer<JsonGenerator, T> serializer,
       ThrowingFunction<JsonParser, T> deserializer) {
     return new Serde<>() {
       @Override
-      public byte[] serialize(@Nullable T value) {
+      public byte[] serialize(T value) {
         ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
         try (JsonGenerator gen = JSON_FACTORY.createGenerator(outputStream)) {
           serializer.asBiConsumer().accept(gen, value);

sdk-common/src/main/java/dev/restate/sdk/common/Serde.java

@@ -11,7 +11,7 @@
 import dev.restate.sdk.common.function.ThrowingFunction;
 import java.nio.ByteBuffer;
 import java.util.Objects;
-import org.jspecify.annotations.Nullable;
+import org.jspecify.annotations.*;
 
 /**
  * Interface defining serialization and deserialization of concrete types.
@@ -22,11 +22,12 @@
  *
  * <p>You can create a custom one using {@link #using(String, ThrowingFunction, ThrowingFunction)}.
  */
-public interface Serde<T> {
+@NullMarked
+public interface Serde<T extends @Nullable Object> {
 
-  byte[] serialize(@Nullable T value);
+  byte[] serialize(T value);
 
-  default ByteBuffer serializeToByteBuffer(@Nullable T value) {
+  default ByteBuffer serializeToByteBuffer(T value) {
     // This is safe because we don't mutate the generated byte[] afterward.
     return ByteBuffer.wrap(serialize(value));
   }
@@ -57,7 +58,7 @@ default T deserialize(ByteBuffer byteBuffer) {
    * Like {@link #using(String, ThrowingFunction, ThrowingFunction)}, using content-type {@code
    * application/octet-stream}.
    */
-  static <T> Serde<T> using(
+  static <T extends @NonNull Object> Serde<@NonNull T> using(
       ThrowingFunction<T, byte[]> serializer, ThrowingFunction<byte[], T> deserializer) {
     return new Serde<>() {
       @Override
@@ -76,7 +77,7 @@ public T deserialize(byte[] value) {
    * Create a {@link Serde} from {@code serializer}/{@code deserializer} lambdas, tagging with
    * {@code contentType}. Before invoking the serializer, we check that {@code value} is non-null.
    */
-  static <T> Serde<T> using(
+  static <T extends @NonNull Object> Serde<@NonNull T> using(
       String contentType,
       ThrowingFunction<T, byte[]> serializer,
       ThrowingFunction<byte[], T> deserializer) {
@@ -92,7 +93,7 @@ public T deserialize(byte[] value) {
       }
 
       @Override
-      public @Nullable String contentType() {
+      public String contentType() {
         return contentType;
       }
     };
@@ -101,12 +102,12 @@ public T deserialize(byte[] value) {
   static <T> Serde<T> withContentType(String contentType, Serde<T> inner) {
     return new Serde<>() {
       @Override
-      public byte[] serialize(@Nullable T value) {
+      public byte[] serialize(T value) {
         return inner.serialize(value);
       }
 
       @Override
-      public ByteBuffer serializeToByteBuffer(@Nullable T value) {
+      public ByteBuffer serializeToByteBuffer(T value) {
         return inner.serializeToByteBuffer(value);
       }
 
@@ -121,22 +122,22 @@ public T deserialize(byte[] value) {
       }
 
       @Override
-      public @Nullable String contentType() {
+      public String contentType() {
         return contentType;
       }
     };
   }
 
   /** Noop {@link Serde} for void. */
-  Serde<Void> VOID =
+  Serde<@Nullable Void> VOID =
       new Serde<>() {
         @Override
         public byte[] serialize(Void value) {
           return new byte[0];
         }
 
         @Override
-        public ByteBuffer serializeToByteBuffer(@Nullable Void value) {
+        public ByteBuffer serializeToByteBuffer(Void value) {
           return ByteBuffer.allocate(0);
         }
 
@@ -151,7 +152,7 @@ public Void deserialize(ByteBuffer byteBuffer) {
         }
 
         @Override
-        public @Nullable String contentType() {
+        public String contentType() {
           return null;
         }
       };
@@ -173,9 +174,8 @@ public byte[] deserialize(byte[] value) {
   /** Pass through {@link Serde} for {@link ByteBuffer}. */
   Serde<ByteBuffer> BYTE_BUFFER =
       new Serde<>() {
-
         @Override
-        public byte[] serialize(@Nullable ByteBuffer byteBuffer) {
+        public byte[] serialize(ByteBuffer byteBuffer) {
           if (byteBuffer == null) {
             return new byte[] {};
           }
@@ -188,7 +188,7 @@ public byte[] serialize(@Nullable ByteBuffer byteBuffer) {
         }
 
         @Override
-        public ByteBuffer serializeToByteBuffer(@Nullable ByteBuffer value) {
+        public ByteBuffer serializeToByteBuffer(ByteBuffer value) {
           return value;
         }
 

sdk-serde-jackson/src/main/java/dev/restate/sdk/serde/jackson/JacksonSerdes.java

@@ -13,7 +13,6 @@
 import com.fasterxml.jackson.databind.ObjectMapper;
 import dev.restate.sdk.common.Serde;
 import java.io.IOException;
-import org.jspecify.annotations.Nullable;
 
 /**
  * {@link Serde} implementations for Jackson.
@@ -57,7 +56,7 @@ public static <T> Serde<T> of(Class<T> clazz) {
   public static <T> Serde<T> of(ObjectMapper mapper, Class<T> clazz) {
     return new Serde<>() {
       @Override
-      public byte[] serialize(@Nullable T value) {
+      public byte[] serialize(T value) {
         try {
           return mapper.writeValueAsBytes(value);
         } catch (JsonProcessingException e) {
@@ -92,7 +91,7 @@ public static <T> Serde<T> of(TypeReference<T> typeReference) {
   public static <T> Serde<T> of(ObjectMapper mapper, TypeReference<T> typeReference) {
     return new Serde<>() {
       @Override
-      public byte[] serialize(@Nullable T value) {
+      public byte[] serialize(T value) {
         try {
           return mapper.writeValueAsBytes(value);
         } catch (JsonProcessingException e) {

settings.gradle.kts

@@ -51,7 +51,7 @@ dependencyResolutionManagement {
       library("opentelemetry-kotlin", "io.opentelemetry", "opentelemetry-extension-kotlin")
           .withoutVersion()
 
-      library("jspecify", "org.jspecify", "jspecify").version("0.3.0")
+      library("jspecify", "org.jspecify", "jspecify").version("1.0.0")
 
       library("jwt", "com.nimbusds:nimbus-jose-jwt:9.37.3")
       library("tink", "com.google.crypto.tink:tink:1.13.0")