Improve generated code in JSON class (#1522)

Author: gcatanese

templates-v7/libraries/jersey3/AbstractOpenApiSchema.mustache

@@ -128,11 +128,7 @@ public abstract class AbstractOpenApiSchema {
      * @return true if it's nullable
      */
     public Boolean isNullable() {
-        if (Boolean.TRUE.equals(isNullable)) {
-            return Boolean.TRUE;
-        } else {
-            return Boolean.FALSE;
-        }
+        return Boolean.TRUE.equals(isNullable);
     }
 
 {{>libraries/jersey2/additional_properties}}

templates-v7/libraries/jersey3/JSON.mustache

@@ -28,10 +28,10 @@ import jakarta.ws.rs.ext.ContextResolver;
 public class JSON implements ContextResolver<ObjectMapper> {
   private static ObjectMapper mapper;
 
-  public JSON() {
+  private JSON() {
     mapper = new ObjectMapper();
     mapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);
-    JsonMapper.builder().configure(MapperFeature.ALLOW_COERCION_OF_SCALARS, false);
+    mapper.configure(MapperFeature.ALLOW_COERCION_OF_SCALARS, true);
     mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
     mapper.configure(DeserializationFeature.FAIL_ON_INVALID_SUBTYPE, true);
     mapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);
@@ -83,7 +83,7 @@ public class JSON implements ContextResolver<ObjectMapper> {
   public static Class<?> getClassForElement(JsonNode node, Class<?> modelClass) {
     ClassDiscriminatorMapping cdm = modelDiscriminators.get(modelClass);
     if (cdm != null) {
-      return cdm.getClassForElement(node, new HashSet<Class<?>>());
+      return cdm.getClassForElement(node, new HashSet<>());
     }
     return null;
   }
@@ -103,7 +103,7 @@ public class JSON implements ContextResolver<ObjectMapper> {
     ClassDiscriminatorMapping(Class<?> cls, String propertyName, Map<String, Class<?>> mappings) {
       modelClass = cls;
       discriminatorName = propertyName;
-      discriminatorMappings = new HashMap<String, Class<?>>();
+      discriminatorMappings = new HashMap<>();
       if (mappings != null) {
         discriminatorMappings.putAll(mappings);
       }
@@ -212,12 +212,12 @@ public class JSON implements ContextResolver<ObjectMapper> {
   /**
    * A map of discriminators for all model classes.
    */
-  private static Map<Class<?>, ClassDiscriminatorMapping> modelDiscriminators = new HashMap<Class<?>, ClassDiscriminatorMapping>();
+  private static final Map<Class<?>, ClassDiscriminatorMapping> modelDiscriminators = new HashMap<Class<?>, ClassDiscriminatorMapping>();
 
   /**
    * A map of oneOf/anyOf descendants for each model class.
    */
-  private static Map<Class<?>, Map<String, GenericType>> modelDescendants = new HashMap<Class<?>, Map<String, GenericType>>();
+  private static final Map<Class<?>, Map<String, GenericType>> modelDescendants = new HashMap<>();
 
   /**
     * Register a model class discriminator.