Mark fields as final where possible
diff --git a/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/AbstractEventLogger.java b/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/AbstractEventLogger.java
index 472b2b9..b573dac 100644
--- a/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/AbstractEventLogger.java
+++ b/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/AbstractEventLogger.java
@@ -42,7 +42,7 @@
 
     private static final int DEFAULT_MAX_LENGTH = 32;
 
-    private static ConstraintPlugins constraintPlugins = ConstraintPlugins.getInstance();
+    private static final ConstraintPlugins constraintPlugins = ConstraintPlugins.getInstance();
 
     public CatalogManager catalogManager;
 
diff --git a/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/ActivityLogger.java b/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/ActivityLogger.java
index 5c1381f..7248019 100644
--- a/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/ActivityLogger.java
+++ b/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/ActivityLogger.java
@@ -31,7 +31,7 @@
     private static final String NAME = "ActivityLogger";
 
     private static final String FQCN = ActivityLogger.class.getName();
-    private static Marker EVENT_MARKER = MarkerManager.getMarker("Activity").addParents(EventLogger.EVENT_MARKER);
+    private static final Marker EVENT_MARKER = MarkerManager.getMarker("Activity").addParents(EventLogger.EVENT_MARKER);
     private static final ExtendedLogger LOGGER = LogManager.getContext(false).getLogger(NAME);
 
     public ActivityLogger() {
diff --git a/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/AuditLogger.java b/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/AuditLogger.java
index d521399..55e2e7a 100644
--- a/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/AuditLogger.java
+++ b/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/AuditLogger.java
@@ -32,7 +32,7 @@
     private static final String NAME = "AuditLogger";
 
     private static final String FQCN = AuditLogger.class.getName();
-    private static Marker EVENT_MARKER = MarkerManager.getMarker("Audit").addParents(EventLogger.EVENT_MARKER);
+    private static final Marker EVENT_MARKER = MarkerManager.getMarker("Audit").addParents(EventLogger.EVENT_MARKER);
     private static final ExtendedLogger LOGGER = LogManager.getContext(false).getLogger(NAME);
 
     public AuditLogger() {
diff --git a/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/AuditMessage.java b/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/AuditMessage.java
index 35b15a5..1b59a32 100644
--- a/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/AuditMessage.java
+++ b/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/AuditMessage.java
@@ -29,7 +29,7 @@
 
     private static final int MAX_LENGTH = 32;
 
-    private Map<String, StructuredDataMessage> extraContent = new HashMap<>();
+    private final Map<String, StructuredDataMessage> extraContent = new HashMap<>();
 
     public AuditMessage(String eventName) {
          this(eventName, MAX_LENGTH);
diff --git a/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/LogEventFactory.java b/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/LogEventFactory.java
index 2bd0051..36d761f 100644
--- a/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/LogEventFactory.java
+++ b/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/LogEventFactory.java
@@ -67,9 +67,9 @@
 
     private static AuditExceptionHandler defaultExceptionHandler = DEFAULT_HANDLER;
 
-    private static ConcurrentMap<Class<?>, List<Property>> classMap = new ConcurrentHashMap<>();
+    private static final ConcurrentMap<Class<?>, List<Property>> classMap = new ConcurrentHashMap<>();
 
-    private static ConstraintPlugins constraintPlugins = ConstraintPlugins.getInstance();
+    private static final ConstraintPlugins constraintPlugins = ConstraintPlugins.getInstance();
 
     public static void setDefaultHandler(AuditExceptionHandler exceptionHandler) {
         defaultExceptionHandler = (exceptionHandler == null) ? NOOP_EXCEPTION_HANDLER : exceptionHandler;
diff --git a/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/catalog/CatalogManagerImpl.java b/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/catalog/CatalogManagerImpl.java
index 2c921a2..6d2c47b 100644
--- a/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/catalog/CatalogManagerImpl.java
+++ b/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/catalog/CatalogManagerImpl.java
@@ -44,11 +44,11 @@
  */
 public class CatalogManagerImpl implements CatalogManager {
 
-    private static Logger logger = LogManager.getLogger(CatalogManagerImpl.class);
+    private static final Logger logger = LogManager.getLogger(CatalogManagerImpl.class);
 
     private volatile Map<String, Map<String, CatalogInfo>> infoMap;
 
-    private Map<String, Attribute> requestContextAttributes = new HashMap<>();
+    private final Map<String, Attribute> requestContextAttributes = new HashMap<>();
 
     protected final Map<String, Map<String, Attribute>> attributeMap = new ConcurrentHashMap<>();
 
diff --git a/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/generator/ClassGenerator.java b/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/generator/ClassGenerator.java
index 8de80c8..6bcebfc 100644
--- a/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/generator/ClassGenerator.java
+++ b/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/generator/ClassGenerator.java
@@ -39,23 +39,23 @@
 public final class ClassGenerator {
     private static final Logger LOGGER = LogManager.getLogger(ClassGenerator.class);
 
-    protected List<AccessorDefinition> beanMethods = new ArrayList<>();
+    protected final List<AccessorDefinition> beanMethods = new ArrayList<>();
     private boolean isClass = true;
-    private String className;
+    private final String className;
     private String parentClassName;
     private String packageName;
-    private String baseFolder;
+    private final String baseFolder;
     private String javadocComment;
     private boolean verbose;
-    private List<String> implementsDeclarations = new ArrayList<>();
+    private final List<String> implementsDeclarations = new ArrayList<>();
 
-    private Set<String> importsDeclarations = new HashSet<>();
+    private final Set<String> importsDeclarations = new HashSet<>();
 
-    private List<VariableDefinition> localVariables = new ArrayList<>();
+    private final List<VariableDefinition> localVariables = new ArrayList<>();
 
-    private List<ConstructorDefinition> constructors = new ArrayList<>();
+    private final List<ConstructorDefinition> constructors = new ArrayList<>();
 
-    private List<MethodDefinition> methods = new ArrayList<>();
+    private final List<MethodDefinition> methods = new ArrayList<>();
 
     private boolean runPrewrite = false;
 
diff --git a/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/generator/MethodDefinition.java b/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/generator/MethodDefinition.java
index 7fa29d1..1dc33ef 100644
--- a/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/generator/MethodDefinition.java
+++ b/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/generator/MethodDefinition.java
@@ -42,7 +42,7 @@
 
     private boolean isInterface = false;
 
-    private List<Parameter> parameters = new ArrayList<>();
+    private final List<Parameter> parameters = new ArrayList<>();
 
     private List<String> exceptions = new ArrayList<>();
 
diff --git a/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/rest/ElapsedUtil.java b/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/rest/ElapsedUtil.java
index 71f899d..3b572bb 100644
--- a/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/rest/ElapsedUtil.java
+++ b/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/rest/ElapsedUtil.java
@@ -20,9 +20,9 @@
 
 public class ElapsedUtil {
 
-    private static long NANO_PER_SECOND = 1000000000L;
-    private static long NANO_PER_MINUTE = NANO_PER_SECOND * 60;
-    private static long NANO_PER_HOUR = NANO_PER_MINUTE * 60;
+    private static final long NANO_PER_SECOND = 1000000000L;
+    private static final long NANO_PER_MINUTE = NANO_PER_SECOND * 60;
+    private static final long NANO_PER_HOUR = NANO_PER_MINUTE * 60;
 
     static void addElapsed(long elapsed, StringBuilder msg) {
         long nanoseconds = elapsed;
diff --git a/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/rest/RequestContextHandlerInterceptor.java b/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/rest/RequestContextHandlerInterceptor.java
index 95fcacb..6ec1bc2 100644
--- a/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/rest/RequestContextHandlerInterceptor.java
+++ b/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/rest/RequestContextHandlerInterceptor.java
@@ -35,8 +35,8 @@
 public class RequestContextHandlerInterceptor implements HandlerInterceptor {
 
     private static final Logger logger = LogManager.getLogger(RequestContextHandlerInterceptor.class);
-    private RequestContextMappings mappings;
-    private ThreadLocal<Long> startTime = new ThreadLocal<>();
+    private final RequestContextMappings mappings;
+    private final ThreadLocal<Long> startTime = new ThreadLocal<>();
 
     public RequestContextHandlerInterceptor(Class<?> clazz) {
         mappings = new RequestContextMappings(clazz);
diff --git a/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/rest/RequestContextHeaderInterceptor.java b/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/rest/RequestContextHeaderInterceptor.java
index ce031e4..cdfba2e 100644
--- a/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/rest/RequestContextHeaderInterceptor.java
+++ b/log4j-audit/log4j-audit-api/src/main/java/org/apache/logging/log4j/audit/rest/RequestContextHeaderInterceptor.java
@@ -37,7 +37,7 @@
  */
 public class RequestContextHeaderInterceptor implements ClientHttpRequestInterceptor {
 
-    private RequestContextMappings mappings;
+    private final RequestContextMappings mappings;
 
     public RequestContextHeaderInterceptor(RequestContextMappings mappings) {
         this.mappings = mappings;
diff --git a/log4j-audit/log4j-audit-api/src/test/java/org/apache/logging/log4j/audit/TransferTest.java b/log4j-audit/log4j-audit-api/src/test/java/org/apache/logging/log4j/audit/TransferTest.java
index e4a1a04..5ca1f52 100644
--- a/log4j-audit/log4j-audit-api/src/test/java/org/apache/logging/log4j/audit/TransferTest.java
+++ b/log4j-audit/log4j-audit-api/src/test/java/org/apache/logging/log4j/audit/TransferTest.java
@@ -45,7 +45,7 @@
  */
 public class TransferTest extends BaseEventTest {
     @Rule
-    public ExpectedException exception = ExpectedException.none();
+    public final ExpectedException exception = ExpectedException.none();
 
     private final String failingAppenderName = "failingAppenderName";
 
diff --git a/log4j-audit/log4j-audit-api/src/test/java/org/apache/logging/log4j/audit/generator/TestInterfacesGenerator.java b/log4j-audit/log4j-audit-api/src/test/java/org/apache/logging/log4j/audit/generator/TestInterfacesGenerator.java
index c4748d2..9a1ce81 100644
--- a/log4j-audit/log4j-audit-api/src/test/java/org/apache/logging/log4j/audit/generator/TestInterfacesGenerator.java
+++ b/log4j-audit/log4j-audit-api/src/test/java/org/apache/logging/log4j/audit/generator/TestInterfacesGenerator.java
@@ -31,7 +31,7 @@
 import static org.junit.Assert.*;
 
 public class TestInterfacesGenerator {
-    private static Logger logger = LogManager.getLogger(TestInterfacesGenerator.class);
+    private static final Logger logger = LogManager.getLogger(TestInterfacesGenerator.class);
     private static ApplicationContext context;
     private static final String GENERATED_SOURCE_DIR = "target/generated-sources/log4j-audit/";
 
diff --git a/log4j-audit/log4j-audit-war/src/main/java/org/apache/logging/log4j/audit/service/catalog/AuditCatalogManager.java b/log4j-audit/log4j-audit-war/src/main/java/org/apache/logging/log4j/audit/service/catalog/AuditCatalogManager.java
index fb05b9b..3b8d340 100644
--- a/log4j-audit/log4j-audit-war/src/main/java/org/apache/logging/log4j/audit/service/catalog/AuditCatalogManager.java
+++ b/log4j-audit/log4j-audit-war/src/main/java/org/apache/logging/log4j/audit/service/catalog/AuditCatalogManager.java
@@ -51,7 +51,7 @@
 
 public class AuditCatalogManager extends CatalogManagerImpl implements AuditManager {
 
-    private static Logger logger = LogManager.getLogger();
+    private static final Logger logger = LogManager.getLogger();
 
     @Autowired
     private CatalogService catalogService;
diff --git a/log4j-audit/log4j-audit-war/src/main/java/org/apache/logging/log4j/audit/service/controller/CatalogController.java b/log4j-audit/log4j-audit-war/src/main/java/org/apache/logging/log4j/audit/service/controller/CatalogController.java
index 53d8a8e..716dc11 100644
--- a/log4j-audit/log4j-audit-war/src/main/java/org/apache/logging/log4j/audit/service/controller/CatalogController.java
+++ b/log4j-audit/log4j-audit-war/src/main/java/org/apache/logging/log4j/audit/service/controller/CatalogController.java
@@ -73,10 +73,10 @@
 
     private static final Logger LOGGER = LogManager.getLogger(CatalogController.class);
 
-    private ModelMapper attributeModelMapper = new ModelMapper();
-    private ModelMapper eventModelMapper = new ModelMapper();
-    private ModelMapper productModelMapper = new ModelMapper();
-    private ModelMapper categoryModelMapper = new ModelMapper();
+    private final ModelMapper attributeModelMapper = new ModelMapper();
+    private final ModelMapper eventModelMapper = new ModelMapper();
+    private final ModelMapper productModelMapper = new ModelMapper();
+    private final ModelMapper categoryModelMapper = new ModelMapper();
 
     @Autowired
     private AttributeService attributeService;
diff --git a/log4j-catalog/log4j-catalog-api/src/main/java/org/apache/logging/log4j/catalog/api/plugins/ConstraintPlugins.java b/log4j-catalog/log4j-catalog-api/src/main/java/org/apache/logging/log4j/catalog/api/plugins/ConstraintPlugins.java
index b2e587f..4ff41c6 100644
--- a/log4j-catalog/log4j-catalog-api/src/main/java/org/apache/logging/log4j/catalog/api/plugins/ConstraintPlugins.java
+++ b/log4j-catalog/log4j-catalog-api/src/main/java/org/apache/logging/log4j/catalog/api/plugins/ConstraintPlugins.java
@@ -35,9 +35,9 @@
 
 public class ConstraintPlugins {
 
-    private static Logger LOGGER = LogManager.getLogger(ConstraintPlugins.class);
+    private static final Logger LOGGER = LogManager.getLogger(ConstraintPlugins.class);
 
-    private static Map<String, ConstraintType> constraintMap = new HashMap<>();
+    private static final Map<String, ConstraintType> constraintMap = new HashMap<>();
 
     private static volatile ConstraintPlugins instance = null;
 
diff --git a/log4j-catalog/log4j-catalog-api/src/main/java/org/apache/logging/log4j/catalog/api/plugins/ConstraintTypeDeserializer.java b/log4j-catalog/log4j-catalog-api/src/main/java/org/apache/logging/log4j/catalog/api/plugins/ConstraintTypeDeserializer.java
index 56e70a7..debbd7a 100644
--- a/log4j-catalog/log4j-catalog-api/src/main/java/org/apache/logging/log4j/catalog/api/plugins/ConstraintTypeDeserializer.java
+++ b/log4j-catalog/log4j-catalog-api/src/main/java/org/apache/logging/log4j/catalog/api/plugins/ConstraintTypeDeserializer.java
@@ -30,7 +30,7 @@
  */
 public class ConstraintTypeDeserializer extends StdDeserializer<ConstraintType> {
 
-    ConstraintPlugins plugins = ConstraintPlugins.getInstance();
+    final ConstraintPlugins plugins = ConstraintPlugins.getInstance();
 
     public ConstraintTypeDeserializer() {
         this(null);
diff --git a/log4j-catalog/log4j-catalog-editor/src/main/java/org/apache/logging/log4j/catalog/config/WebAppInitializer.java b/log4j-catalog/log4j-catalog-editor/src/main/java/org/apache/logging/log4j/catalog/config/WebAppInitializer.java
index 12824ec..9c9368f 100644
--- a/log4j-catalog/log4j-catalog-editor/src/main/java/org/apache/logging/log4j/catalog/config/WebAppInitializer.java
+++ b/log4j-catalog/log4j-catalog-editor/src/main/java/org/apache/logging/log4j/catalog/config/WebAppInitializer.java
@@ -24,7 +24,7 @@
 
 public class WebAppInitializer {
     private static final String APPLICATION_NAME = "AuditCatalog";
-    private static Logger LOGGER = LogManager.getLogger(WebAppInitializer.class);
+    private static final Logger LOGGER = LogManager.getLogger(WebAppInitializer.class);
 
     @Bean
     public ServletContextInitializer initializer() {
diff --git a/log4j-catalog/log4j-catalog-editor/src/main/java/org/apache/logging/log4j/catalog/controller/AttributeController.java b/log4j-catalog/log4j-catalog-editor/src/main/java/org/apache/logging/log4j/catalog/controller/AttributeController.java
index 5c93811..5f3bfbc 100644
--- a/log4j-catalog/log4j-catalog-editor/src/main/java/org/apache/logging/log4j/catalog/controller/AttributeController.java
+++ b/log4j-catalog/log4j-catalog-editor/src/main/java/org/apache/logging/log4j/catalog/controller/AttributeController.java
@@ -53,9 +53,9 @@
 @RequestMapping(value = "/api/attributes")
 @RestController
 public class AttributeController {
-    private static ConstraintPlugins constraintPlugins = ConstraintPlugins.getInstance();
+    private static final ConstraintPlugins constraintPlugins = ConstraintPlugins.getInstance();
 
-    private ModelMapper modelMapper = new ModelMapper();
+    private final ModelMapper modelMapper = new ModelMapper();
 
     @Autowired
     private AttributeService attributeService;
diff --git a/log4j-catalog/log4j-catalog-editor/src/main/java/org/apache/logging/log4j/catalog/controller/CategoryController.java b/log4j-catalog/log4j-catalog-editor/src/main/java/org/apache/logging/log4j/catalog/controller/CategoryController.java
index 1d2cb95..16ef136 100644
--- a/log4j-catalog/log4j-catalog-editor/src/main/java/org/apache/logging/log4j/catalog/controller/CategoryController.java
+++ b/log4j-catalog/log4j-catalog-editor/src/main/java/org/apache/logging/log4j/catalog/controller/CategoryController.java
@@ -47,7 +47,7 @@
 @RestController
 public class CategoryController {
 
-    private ModelMapper modelMapper = new ModelMapper();
+    private final ModelMapper modelMapper = new ModelMapper();
 
     @Autowired
     private CategoryService categoryService;
diff --git a/log4j-catalog/log4j-catalog-editor/src/main/java/org/apache/logging/log4j/catalog/controller/ConstraintController.java b/log4j-catalog/log4j-catalog-editor/src/main/java/org/apache/logging/log4j/catalog/controller/ConstraintController.java
index 4a552e7..efa3887 100644
--- a/log4j-catalog/log4j-catalog-editor/src/main/java/org/apache/logging/log4j/catalog/controller/ConstraintController.java
+++ b/log4j-catalog/log4j-catalog-editor/src/main/java/org/apache/logging/log4j/catalog/controller/ConstraintController.java
@@ -49,7 +49,7 @@
 @RestController
 public class ConstraintController {
 
-    private ModelMapper modelMapper = new ModelMapper();
+    private final ModelMapper modelMapper = new ModelMapper();
 
     @Autowired
     private ConstraintService constraintService;
diff --git a/log4j-catalog/log4j-catalog-editor/src/main/java/org/apache/logging/log4j/catalog/controller/EventController.java b/log4j-catalog/log4j-catalog-editor/src/main/java/org/apache/logging/log4j/catalog/controller/EventController.java
index dd68682..89b9a94 100644
--- a/log4j-catalog/log4j-catalog-editor/src/main/java/org/apache/logging/log4j/catalog/controller/EventController.java
+++ b/log4j-catalog/log4j-catalog-editor/src/main/java/org/apache/logging/log4j/catalog/controller/EventController.java
@@ -16,21 +16,13 @@
  */
 package org.apache.logging.log4j.catalog.controller;
 
-import javax.annotation.PostConstruct;
-import java.lang.reflect.Type;
-import java.util.ArrayList;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-import java.util.Optional;
-
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.catalog.api.Event;
-import org.apache.logging.log4j.catalog.jpa.model.EventModel;
-import org.apache.logging.log4j.catalog.jpa.service.EventService;
 import org.apache.logging.log4j.catalog.jpa.converter.EventConverter;
 import org.apache.logging.log4j.catalog.jpa.converter.EventModelConverter;
+import org.apache.logging.log4j.catalog.jpa.model.EventModel;
+import org.apache.logging.log4j.catalog.jpa.service.EventService;
 import org.modelmapper.ModelMapper;
 import org.modelmapper.TypeToken;
 import org.springframework.beans.factory.annotation.Autowired;
@@ -42,6 +34,14 @@
 import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.bind.annotation.RestController;
 
+import javax.annotation.PostConstruct;
+import java.lang.reflect.Type;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+
 /**
  * Catalog Product controller
  */
@@ -51,7 +51,7 @@
 public class EventController {
     private static final Logger LOGGER = LogManager.getLogger();
 
-    private ModelMapper modelMapper = new ModelMapper();
+    private final ModelMapper modelMapper = new ModelMapper();
 
     @Autowired
     private EventService eventService;
diff --git a/log4j-catalog/log4j-catalog-editor/src/main/java/org/apache/logging/log4j/catalog/controller/ProductController.java b/log4j-catalog/log4j-catalog-editor/src/main/java/org/apache/logging/log4j/catalog/controller/ProductController.java
index e82a384..f24d8a5 100644
--- a/log4j-catalog/log4j-catalog-editor/src/main/java/org/apache/logging/log4j/catalog/controller/ProductController.java
+++ b/log4j-catalog/log4j-catalog-editor/src/main/java/org/apache/logging/log4j/catalog/controller/ProductController.java
@@ -47,7 +47,7 @@
 @RestController
 public class ProductController {
 
-    private ModelMapper modelMapper = new ModelMapper();
+    private final ModelMapper modelMapper = new ModelMapper();
 
     @Autowired
     private ProductService productService;
diff --git a/log4j-catalog/log4j-catalog-jpa/src/main/java/org/apache/logging/log4j/catalog/jpa/config/EclipseLinkConfig.java b/log4j-catalog/log4j-catalog-jpa/src/main/java/org/apache/logging/log4j/catalog/jpa/config/EclipseLinkConfig.java
index 9ff9569..1645c24 100644
--- a/log4j-catalog/log4j-catalog-jpa/src/main/java/org/apache/logging/log4j/catalog/jpa/config/EclipseLinkConfig.java
+++ b/log4j-catalog/log4j-catalog-jpa/src/main/java/org/apache/logging/log4j/catalog/jpa/config/EclipseLinkConfig.java
@@ -39,7 +39,7 @@
 @Profile("eclipseLink")
 public class EclipseLinkConfig {
 
-    private static Logger LOGGER = LogManager.getLogger(EclipseLinkConfig.class);
+    private static final Logger LOGGER = LogManager.getLogger(EclipseLinkConfig.class);
 
     @Autowired
     private DataSourceConfig dataSourceConfig;
diff --git a/log4j-catalog/log4j-catalog-jpa/src/main/java/org/apache/logging/log4j/catalog/jpa/converter/AttributeConverter.java b/log4j-catalog/log4j-catalog-jpa/src/main/java/org/apache/logging/log4j/catalog/jpa/converter/AttributeConverter.java
index ba8962d..f8a6292 100644
--- a/log4j-catalog/log4j-catalog-jpa/src/main/java/org/apache/logging/log4j/catalog/jpa/converter/AttributeConverter.java
+++ b/log4j-catalog/log4j-catalog-jpa/src/main/java/org/apache/logging/log4j/catalog/jpa/converter/AttributeConverter.java
@@ -37,7 +37,7 @@
  */
 @Component
 public class AttributeConverter extends AbstractConverter<Attribute, AttributeModel> {
-    private static Logger LOGGER = LogManager.getLogger(AttributeConverter.class);
+    private static final Logger LOGGER = LogManager.getLogger(AttributeConverter.class);
 
     @Autowired
     private AttributeService attributeService;
diff --git a/log4j-catalog/log4j-catalog-jpa/src/main/java/org/apache/logging/log4j/catalog/jpa/converter/EventConverter.java b/log4j-catalog/log4j-catalog-jpa/src/main/java/org/apache/logging/log4j/catalog/jpa/converter/EventConverter.java
index 388252b..60c181d 100644
--- a/log4j-catalog/log4j-catalog-jpa/src/main/java/org/apache/logging/log4j/catalog/jpa/converter/EventConverter.java
+++ b/log4j-catalog/log4j-catalog-jpa/src/main/java/org/apache/logging/log4j/catalog/jpa/converter/EventConverter.java
@@ -41,7 +41,7 @@
  */
 @Component
 public class EventConverter extends AbstractConverter<Event, EventModel> {
-    private static Logger LOGGER = LogManager.getLogger(EventConverter.class);
+    private static final Logger LOGGER = LogManager.getLogger(EventConverter.class);
 
     @Autowired
     private EventService eventService;