Update CHANGELOG

Author: mpkorstanje

CHANGELOG.md

@@ -6,6 +6,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Fixed
+- Improved Javadoc
 
 ## [0.2.0] - 2026-01-12
 ### Added

java/src/main/java/io/cucumber/messages/ndjson/Deserializer.java

@@ -7,10 +7,24 @@
 
 import static java.util.Objects.requireNonNull;
 
+/**
+ * Deserializes a JSON string to a message.
+ */
 public final class Deserializer implements NdjsonToMessageIterable.Deserializer {
 
     /**
-     * Reads the given {@code json} and converts it to a link {@link Envelope}
+     * Deserialize a JSON string to message.
+     *
+     * <ul>
+     *     <li>Values must be included unless their value is {@code null}
+     *     or an "absent" reference values such as empty optionals.
+     *     <li>Enums must be read as strings.
+     *     <li>Unknown properties must be ignored.
+     * </ul>
+     *
+     * @param json to deserialize
+     * @return a deserialized {@link Envelope} or null
+     * @throws IOException if anything goes wrong
      */
     @Override
     public Envelope readValue(String json) throws IOException {

java/src/main/java/io/cucumber/messages/ndjson/Serializer.java

@@ -6,11 +6,26 @@
 import java.io.IOException;
 import java.io.Writer;
 
+/**
+ * Serializes a message to a single line of JSON.
+ */
 public final class Serializer implements MessageToNdjsonWriter.Serializer {
 
     /**
-     * Converts a given {@link Envelope} to single line of JSON and writes it
-     * to the given writer.
+     * Serialize a message to single line of JSON and write it to the
+     * given {@code writer}.
+     *
+     * <ul>
+     *     <li>Values must be included unless their value is {@code null}
+     *     or an "absent" reference values such as empty optionals.
+     *     <li>Enums must be written as strings.
+     *     <li>Implementations may not close the {@code writer} after
+     *     writing a {@code value}.
+     * </ul>
+     *
+     * @param writer to write to
+     * @param value  to serialize
+     * @throws IOException if anything goes wrong
      */
     @Override
     public void writeValue(Writer writer, Envelope value) throws IOException {