diff --git a/modules/openapi-generator-maven-plugin/src/main/java/org/openapitools/codegen/plugin/CodeGenMojo.java b/modules/openapi-generator-maven-plugin/src/main/java/org/openapitools/codegen/plugin/CodeGenMojo.java
index aa386a2995f3..0d33707e32d6 100644
--- a/modules/openapi-generator-maven-plugin/src/main/java/org/openapitools/codegen/plugin/CodeGenMojo.java
+++ b/modules/openapi-generator-maven-plugin/src/main/java/org/openapitools/codegen/plugin/CodeGenMojo.java
@@ -70,7 +70,7 @@
  * Goal which generates client/server code from a OpenAPI json/yaml definition.
  */
 @SuppressWarnings({"unused", "MismatchedQueryAndUpdateOfCollection"})
-@Mojo(name = "generate", defaultPhase = LifecyclePhase.GENERATE_SOURCES)
+@Mojo(name = "generate", defaultPhase = LifecyclePhase.GENERATE_SOURCES, threadSafe = true)
 public class CodeGenMojo extends AbstractMojo {
 
     private static final Logger LOGGER = LoggerFactory.getLogger(CodeGenMojo.class);
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/config/CodegenConfigurator.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/config/CodegenConfigurator.java
index a60f824278b1..840790ed4c8d 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/config/CodegenConfigurator.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/config/CodegenConfigurator.java
@@ -79,67 +79,72 @@ public CodegenConfigurator() {
     public static CodegenConfigurator fromFile(String configFile, Module... modules) {
 
         if (isNotEmpty(configFile)) {
-            ObjectMapper mapper;
+            DynamicSettings settings = readDynamicSettings(configFile, modules);
 
-            if (FilenameUtils.isExtension(configFile, new String[]{"yml", "yaml"})) {
-                mapper = Yaml.mapper();
-            } else {
-                mapper = Json.mapper();
-            }
+            CodegenConfigurator configurator = new CodegenConfigurator();
 
-            if (modules != null && modules.length > 0) {
-                mapper.registerModules(modules);
+            GeneratorSettings generatorSettings = settings.getGeneratorSettings();
+            WorkflowSettings workflowSettings = settings.getWorkflowSettings();
+
+            // We copy "cached" properties into configurator so it is appropriately configured with all settings in external files.
+            // FIXME: target is to eventually move away from CodegenConfigurator properties except gen/workflow settings.
+            configurator.generatorName = generatorSettings.getGeneratorName();
+            configurator.inputSpec = workflowSettings.getInputSpec();
+            configurator.templatingEngineName = workflowSettings.getTemplatingEngineName();
+            if (workflowSettings.getSystemProperties() != null) {
+                configurator.systemProperties.putAll(workflowSettings.getSystemProperties());
+            }
+            if(generatorSettings.getInstantiationTypes() != null) {
+                configurator.instantiationTypes.putAll(generatorSettings.getInstantiationTypes());
+            }
+            if(generatorSettings.getTypeMappings() != null) {
+                configurator.typeMappings.putAll(generatorSettings.getTypeMappings());
+            }
+            if(generatorSettings.getAdditionalProperties() != null) {
+                configurator.additionalProperties.putAll(generatorSettings.getAdditionalProperties());
+            }
+            if(generatorSettings.getImportMappings() != null) {
+                configurator.importMappings.putAll(generatorSettings.getImportMappings());
+            }
+            if(generatorSettings.getLanguageSpecificPrimitives() != null) {
+                configurator.languageSpecificPrimitives.addAll(generatorSettings.getLanguageSpecificPrimitives());
+            }
+            if(generatorSettings.getReservedWordMappings() != null) {
+                configurator.reservedWordMappings.putAll(generatorSettings.getReservedWordMappings());
+            }
+            if(generatorSettings.getServerVariables() != null) {
+                configurator.serverVariables.putAll(generatorSettings.getServerVariables());
             }
 
-            mapper.registerModule(new GuavaModule());
+            configurator.generatorSettingsBuilder = GeneratorSettings.newBuilder(generatorSettings);
+            configurator.workflowSettingsBuilder = WorkflowSettings.newBuilder(workflowSettings);
 
-            try {
-                DynamicSettings settings = mapper.readValue(new File(configFile), DynamicSettings.class);
-                CodegenConfigurator configurator = new CodegenConfigurator();
+            return configurator;
+        }
+        return null;
+    }
 
-                GeneratorSettings generatorSettings = settings.getGeneratorSettings();
-                WorkflowSettings workflowSettings = settings.getWorkflowSettings();
+    private static DynamicSettings readDynamicSettings(String configFile, Module... modules) {
+        ObjectMapper mapper;
 
-                // We copy "cached" properties into configurator so it is appropriately configured with all settings in external files.
-                // FIXME: target is to eventually move away from CodegenConfigurator properties except gen/workflow settings.
-                configurator.generatorName = generatorSettings.getGeneratorName();
-                configurator.inputSpec = workflowSettings.getInputSpec();
-                configurator.templatingEngineName = workflowSettings.getTemplatingEngineName();
-                if (workflowSettings.getSystemProperties() != null) {
-                    configurator.systemProperties.putAll(workflowSettings.getSystemProperties());
-                }
-                if(generatorSettings.getInstantiationTypes() != null) {
-                    configurator.instantiationTypes.putAll(generatorSettings.getInstantiationTypes());
-                }
-                if(generatorSettings.getTypeMappings() != null) {
-                    configurator.typeMappings.putAll(generatorSettings.getTypeMappings());
-                }
-                if(generatorSettings.getAdditionalProperties() != null) {
-                    configurator.additionalProperties.putAll(generatorSettings.getAdditionalProperties());
-                }
-                if(generatorSettings.getImportMappings() != null) {
-                    configurator.importMappings.putAll(generatorSettings.getImportMappings());
-                }
-                if(generatorSettings.getLanguageSpecificPrimitives() != null) {
-                    configurator.languageSpecificPrimitives.addAll(generatorSettings.getLanguageSpecificPrimitives());
-                }
-                if(generatorSettings.getReservedWordMappings() != null) {
-                    configurator.reservedWordMappings.putAll(generatorSettings.getReservedWordMappings());
-                }
-                if(generatorSettings.getServerVariables() != null) {
-                    configurator.serverVariables.putAll(generatorSettings.getServerVariables());
-                }
+        if (FilenameUtils.isExtension(configFile.toLowerCase(Locale.ROOT), new String[]{"yml", "yaml"})) {
+            mapper = Yaml.mapper().copy();
+        } else {
+            mapper = Json.mapper().copy();
+        }
+
+        if (modules != null && modules.length > 0) {
+            mapper.registerModules(modules);
+        }
 
-                configurator.generatorSettingsBuilder = GeneratorSettings.newBuilder(generatorSettings);
-                configurator.workflowSettingsBuilder = WorkflowSettings.newBuilder(workflowSettings);
+        mapper.registerModule(new GuavaModule());
 
-                return configurator;
-            } catch (IOException ex) {
-                LOGGER.error(ex.getMessage());
-                throw new RuntimeException("Unable to deserialize config file: " + configFile);
-            }
+        try {
+            return mapper.readValue(new File(configFile), DynamicSettings.class);
+        } catch (IOException ex) {
+            LOGGER.error(ex.getMessage());
+            throw new RuntimeException("Unable to deserialize config file: " + configFile);
         }
-        return null;
     }
 
     public CodegenConfigurator addServerVariable(String key, String value) {