Improve javadoc

Author: rbygrave

jsonb-jackson/src/main/java/io/avaje/jsonb/jackson/JacksonAdapter.java

@@ -14,7 +14,42 @@
 import java.io.*;
 
 /**
- * Jackson Core implementation of IOAdapter.
+ * Jackson Core implementation of JsonStreamAdapter.
+ * <p>
+ * This uses the JsonParser and JsonGenerator of Jackson core to do the underlying parsing and
+ * generation.
+ *
+ * <h3>Explicitly initialise</h3>
+ * <p>
+ * We can use it explicitly using code like:
+ *
+ * <pre>{@code
+ *
+ * JsonFactory customFactory = ...;
+ *
+ * var jacksonAdapter = JacksonAdapter.newBuilder()
+ *   .serializeNulls(true)
+ *   .jsonFactory(customFactory)
+ *   .build();
+ *
+ * Jsonb jsonb = Jsonb.newBuilder()
+ *   .adapter(jacksonAdapter)
+ *   .build();
+ *
+ * }</pre>
+ *
+ * <h3>Service loading initialise</h3>
+ * <p>
+ * Including the <code>io.avaje:avaje-jsonb-jackson</em> dependency in the classpath means that this
+ * JacksonAdapter will be automatically used via service loading.
+ * <p>
+ * In this automatic service loading case the defaults are:
+ * <ul>
+ *   <li>new JsonFactory()</li>
+ *   <li>serializeNulls false</li>
+ *   <li>serializeEmpty false</li>
+ *   <li>failOnUnknown false</li>
+ * </ul>
  */
 public class JacksonAdapter implements JsonStreamAdapter {
 
@@ -112,6 +147,10 @@ public JacksonAdapter(boolean serializeNulls, boolean serializeEmpty, boolean fa
    *   .jsonFactory(customFactory)
    *   .build();
    *
+   * Jsonb jsonb = Jsonb.newBuilder()
+   *   .adapter(jacksonAdapter)
+   *   .build();
+   *
    * }</pre>
    */
   public static Builder newBuilder() {

jsonb/src/main/java/io/avaje/jsonb/Jsonb.java

@@ -33,6 +33,27 @@
  *     .build();
  * }</pre>
  *
+ * <h4>Initialise using Jackson core with configuration</h3>
+ * <p>
+ * We need to include the dependency <code>io.avaje:avaje-jsonb-jackson</code> to do this.
+ * This will use Jackson core JsonParser and JsonGenerator to do the underlying parsing and generation.
+ * </p>
+ * <pre>{@code
+ *
+ *   // create the Jackson JsonFactory
+ *   JsonFactory customFactory = ...;
+ *
+ *   var jacksonAdapter = JacksonAdapter.newBuilder()
+ *     .serializeNulls(true)
+ *     .jsonFactory(customFactory)
+ *     .build();
+ *
+ *   Jsonb jsonb = Jsonb.newBuilder()
+ *     .adapter(jacksonAdapter)
+ *     .build();
+ *
+ * }</pre>
+ *
  * <h4>fromJson</h4>
  * <p>
  * Read json content from: String, byte[], Reader, InputStream, JsonReader