Use initialization-on-demand holder

Signed-off-by: Matheus Cruz <matheuscruz.dev@gmail.com>

Author: mcruzdev

impl/core/src/main/java/io/serverlessworkflow/impl/WorkflowApplication.java

@@ -245,7 +245,7 @@ public SchemaValidator getValidator(SchemaInline inline) {
     private WorkflowModelFactory modelFactory;
     private WorkflowModelFactory contextFactory;
     private Map<String, WorkflowAdditionalObject<?>> additionalObjects = new HashMap<>();
-    private AuthProviderFactory authProviderFactory = DefaultAuthProviderFactory.INSTANCE;
+    private AuthProviderFactory authProviderFactory;
     private SecretManager secretManager;
     private ConfigManager configManager;
     private SchedulerListener schedulerListener;
@@ -480,6 +480,10 @@ public WorkflowApplication build() {
       if (id == null) {
         id = idFactory.get();
       }
+      if (authProviderFactory == null) {
+        authProviderFactory = DefaultAuthProviderFactory.factory();
+      }
+
       return new WorkflowApplication(this);
     }
 

impl/core/src/main/java/io/serverlessworkflow/impl/auth/DefaultAuthProviderFactory.java

@@ -27,7 +27,13 @@
 
 public class DefaultAuthProviderFactory implements AuthProviderFactory {
 
-  public static final DefaultAuthProviderFactory INSTANCE = new DefaultAuthProviderFactory();
+  private static class DefaultAuthProviderFactoryHolder {
+    private static final DefaultAuthProviderFactory instance = new DefaultAuthProviderFactory();
+  }
+
+  public static DefaultAuthProviderFactory factory() {
+    return DefaultAuthProviderFactoryHolder.instance;
+  }
 
   @Override
   public Optional<AuthProvider> getAuth(

impl/http/src/main/java/io/serverlessworkflow/impl/executors/http/HttpExecutorBuilder.java

@@ -103,7 +103,7 @@ public static HttpExecutorBuilder builder(WorkflowDefinition definition) {
   private RequestExecutor buildRequestExecutor() {
     String httpMethod = method.toUpperCase();
     Optional<AuthProvider> auth =
-        definition.application().authProviderFactory().getAuth(definition, policy, method);
+        definition.application().authProviderFactory().getAuth(definition, policy, httpMethod);
     return switch (httpMethod) {
       case HttpMethod.POST, HttpMethod.PUT, HttpMethod.PATCH ->
           new WithBodyRequestExecutor(httpMethod, redirect, auth, definition.application(), body);