diff --git a/external-reports/src/main/java/org/sonar/java/externalreport/SpotBugsXmlReportReader.java b/external-reports/src/main/java/org/sonar/java/externalreport/SpotBugsXmlReportReader.java
index ea463fcd325..7f943049f58 100644
--- a/external-reports/src/main/java/org/sonar/java/externalreport/SpotBugsXmlReportReader.java
+++ b/external-reports/src/main/java/org/sonar/java/externalreport/SpotBugsXmlReportReader.java
@@ -50,7 +50,7 @@ public class SpotBugsXmlReportReader {
   private final ExternalRuleLoader defaultRuleLoader;
   private final Map<String, ExternalRuleLoader> otherLoaders;
 
-  private List<String> sourceDirs = new ArrayList<>();
+  private final List<String> sourceDirs = new ArrayList<>();
   private String bugInstanceType = "";
   private String bugInstanceLongMessage = "";
   private String sourceLinePath = "";
diff --git a/java-checks-aws/src/main/java/org/sonar/java/checks/aws/AwsBuilderMethodFinder.java b/java-checks-aws/src/main/java/org/sonar/java/checks/aws/AwsBuilderMethodFinder.java
index 06ceed6dfa5..2788603afe9 100644
--- a/java-checks-aws/src/main/java/org/sonar/java/checks/aws/AwsBuilderMethodFinder.java
+++ b/java-checks-aws/src/main/java/org/sonar/java/checks/aws/AwsBuilderMethodFinder.java
@@ -144,7 +144,7 @@ private static boolean isPassedAsArgument(IdentifierTree identifier) {
 
   private static class CallChainVisitor extends BaseTreeVisitor {
     protected boolean methodIsInvoked;
-    private MethodMatchers target;
+    private final MethodMatchers target;
 
     CallChainVisitor(MethodMatchers matcher) {
       this.target = matcher;
diff --git a/java-checks-common/src/main/java/org/sonar/java/checks/helpers/ExpressionsHelper.java b/java-checks-common/src/main/java/org/sonar/java/checks/helpers/ExpressionsHelper.java
index 6d7cb8a7f94..28358aed28d 100644
--- a/java-checks-common/src/main/java/org/sonar/java/checks/helpers/ExpressionsHelper.java
+++ b/java-checks-common/src/main/java/org/sonar/java/checks/helpers/ExpressionsHelper.java
@@ -157,8 +157,8 @@ private static boolean isStrictAssignmentOrDeclaration(ExpressionTree expression
 
   public static class ValueResolution<T> {
     private T value;
-    private List<JavaFileScannerContext.Location> valuePath = new ArrayList<>();
-    private Set<Symbol> evaluatedSymbols = new HashSet<>();
+    private final List<JavaFileScannerContext.Location> valuePath = new ArrayList<>();
+    private final Set<Symbol> evaluatedSymbols = new HashSet<>();
     private final String locationMessage;
 
     public ValueResolution() {
diff --git a/java-checks-testkit/src/main/java/org/sonar/java/checks/verifier/internal/Expectations.java b/java-checks-testkit/src/main/java/org/sonar/java/checks/verifier/internal/Expectations.java
index 6acdca5dad3..e514f7f8b2e 100644
--- a/java-checks-testkit/src/main/java/org/sonar/java/checks/verifier/internal/Expectations.java
+++ b/java-checks-testkit/src/main/java/org/sonar/java/checks/verifier/internal/Expectations.java
@@ -107,7 +107,7 @@ enum IssueAttribute {
     FLOWS(multiValueAttribute(Function.identity())),
     QUICK_FIXES(multiValueAttribute(Function.identity()));
 
-    private Function<String, ?> setter;
+    private final Function<String, ?> setter;
     private Function<Object, Object> getter = Function.identity();
 
     IssueAttribute(Function<String, ?> setter) {
@@ -247,7 +247,7 @@ private static int getColumnOffset(@Nullable Object o, String position, int line
   private boolean collectQuickFixes = false;
   private final Map<AnalyzerMessage.TextSpan, List<JavaQuickFix>> quickFixes = new HashMap<>();
 
-  private Set<String> seenFlowIds = new HashSet<>();
+  private final Set<String> seenFlowIds = new HashSet<>();
 
   Expectations() {
   }
diff --git a/java-checks-testkit/src/main/java/org/sonar/java/checks/verifier/internal/InternalCacheContext.java b/java-checks-testkit/src/main/java/org/sonar/java/checks/verifier/internal/InternalCacheContext.java
index 14872a48a5a..f8cf36a1286 100644
--- a/java-checks-testkit/src/main/java/org/sonar/java/checks/verifier/internal/InternalCacheContext.java
+++ b/java-checks-testkit/src/main/java/org/sonar/java/checks/verifier/internal/InternalCacheContext.java
@@ -24,9 +24,9 @@
 import java.util.Objects;
 
 public class InternalCacheContext implements CacheContext {
-  private boolean isEnabled;
-  private JavaReadCache readCache;
-  private JavaWriteCache writeCache;
+  private final boolean isEnabled;
+  private final JavaReadCache readCache;
+  private final JavaWriteCache writeCache;
 
   public InternalCacheContext(boolean isEnabled, @Nullable JavaReadCache readCache, @Nullable JavaWriteCache writeCache) {
     this.isEnabled = isEnabled;
diff --git a/java-checks-testkit/src/main/java/org/sonar/java/checks/verifier/internal/InternalCheckVerifier.java b/java-checks-testkit/src/main/java/org/sonar/java/checks/verifier/internal/InternalCheckVerifier.java
index 791c4307503..6f55fa99bfb 100644
--- a/java-checks-testkit/src/main/java/org/sonar/java/checks/verifier/internal/InternalCheckVerifier.java
+++ b/java-checks-testkit/src/main/java/org/sonar/java/checks/verifier/internal/InternalCheckVerifier.java
@@ -90,7 +90,7 @@ public class InternalCheckVerifier implements CheckVerifier {
   private Consumer<Set<AnalyzerMessage>> customIssueVerifier = null;
   private boolean collectQuickFixes = false;
 
-  private Expectations expectations = new Expectations();
+  private final Expectations expectations = new Expectations();
   @VisibleForTesting
   CacheContext cacheContext = null;
   private ReadCache readCache;
diff --git a/java-checks-testkit/src/main/java/org/sonar/java/checks/verifier/internal/JavaCheckVerifier.java b/java-checks-testkit/src/main/java/org/sonar/java/checks/verifier/internal/JavaCheckVerifier.java
index 32dc881dfff..adbeb122b90 100644
--- a/java-checks-testkit/src/main/java/org/sonar/java/checks/verifier/internal/JavaCheckVerifier.java
+++ b/java-checks-testkit/src/main/java/org/sonar/java/checks/verifier/internal/JavaCheckVerifier.java
@@ -78,8 +78,8 @@ public static JavaCheckVerifier newInstance() {
 
   private List<JavaFileScanner> checks = null;
   private List<File> classpath = null;
-  private List<String> jarsToAdd = new ArrayList<>();
-  private List<String> jarsToRemove = new ArrayList<>();
+  private final List<String> jarsToAdd = new ArrayList<>();
+  private final List<String> jarsToRemove = new ArrayList<>();
   @VisibleForTesting
   List<File> actualClasspath = null;
   private JavaVersion javaVersion = null;
diff --git a/java-checks/src/main/java/org/sonar/java/checks/AbstractInSynchronizeChecker.java b/java-checks/src/main/java/org/sonar/java/checks/AbstractInSynchronizeChecker.java
index f865390c5bd..b82c9d62d28 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/AbstractInSynchronizeChecker.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/AbstractInSynchronizeChecker.java
@@ -29,7 +29,7 @@
 import java.util.List;
 
 public abstract class AbstractInSynchronizeChecker extends AbstractMethodDetection {
-  private Deque<Boolean> withinSynchronizedBlock = new LinkedList<>();
+  private final Deque<Boolean> withinSynchronizedBlock = new LinkedList<>();
 
   @Override
   public void setContext(JavaFileScannerContext context) {
diff --git a/java-checks/src/main/java/org/sonar/java/checks/AccessibilityChangeOnRecordsCheck.java b/java-checks/src/main/java/org/sonar/java/checks/AccessibilityChangeOnRecordsCheck.java
index 658adac8a7f..b3a190385bc 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/AccessibilityChangeOnRecordsCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/AccessibilityChangeOnRecordsCheck.java
@@ -37,8 +37,8 @@ public class AccessibilityChangeOnRecordsCheck extends AbstractAccessibilityChan
   private static final String MESSAGE = "Remove this private field update which will never succeed";
   private static final String SECONDARY_MESSAGE = "Remove this accessibility bypass which will never succeed";
 
-  private Map<Symbol, MethodInvocationTree> primaryTargets = new HashMap<>();
-  private Map<Symbol, List<MethodInvocationTree>> secondaryTargets = new HashMap<>();
+  private final Map<Symbol, MethodInvocationTree> primaryTargets = new HashMap<>();
+  private final Map<Symbol, List<MethodInvocationTree>> secondaryTargets = new HashMap<>();
 
   @Override
   public List<Tree.Kind> nodesToVisit() {
diff --git a/java-checks/src/main/java/org/sonar/java/checks/CastArithmeticOperandCheck.java b/java-checks/src/main/java/org/sonar/java/checks/CastArithmeticOperandCheck.java
index 900632c6f65..a0d64da5e80 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/CastArithmeticOperandCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/CastArithmeticOperandCheck.java
@@ -156,7 +156,7 @@ private static boolean isVarTypeErrorProne(Type varType) {
   }
 
   private class ReturnStatementVisitor extends BaseTreeVisitor {
-    private Type returnType;
+    private final Type returnType;
 
     public ReturnStatementVisitor(Type returnType) {
       this.returnType = returnType;
diff --git a/java-checks/src/main/java/org/sonar/java/checks/ClassVariableVisibilityCheck.java b/java-checks/src/main/java/org/sonar/java/checks/ClassVariableVisibilityCheck.java
index e9cde2e8f94..dc358355c25 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/ClassVariableVisibilityCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/ClassVariableVisibilityCheck.java
@@ -36,7 +36,7 @@
 @Rule(key = "S1104")
 public class ClassVariableVisibilityCheck extends BaseTreeVisitor implements JavaFileScanner {
 
-  private Deque<Boolean> isClassStack = new ArrayDeque<>();
+  private final Deque<Boolean> isClassStack = new ArrayDeque<>();
 
   private JavaFileScannerContext context;
 
diff --git a/java-checks/src/main/java/org/sonar/java/checks/CollapsibleIfCandidateCheck.java b/java-checks/src/main/java/org/sonar/java/checks/CollapsibleIfCandidateCheck.java
index 204fd9366b9..971698ad7b3 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/CollapsibleIfCandidateCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/CollapsibleIfCandidateCheck.java
@@ -35,7 +35,7 @@
 public class CollapsibleIfCandidateCheck extends BaseTreeVisitor implements JavaFileScanner {
 
   private JavaFileScannerContext context;
-  private Deque<IfStatementTree> outerIf = new ArrayDeque<>();
+  private final Deque<IfStatementTree> outerIf = new ArrayDeque<>();
 
   @Override
   public void scanFile(JavaFileScannerContext context) {
diff --git a/java-checks/src/main/java/org/sonar/java/checks/CollectionInappropriateCallsCheck.java b/java-checks/src/main/java/org/sonar/java/checks/CollectionInappropriateCallsCheck.java
index 5421aeb1f70..8e98906978c 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/CollectionInappropriateCallsCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/CollectionInappropriateCallsCheck.java
@@ -176,7 +176,7 @@ private static class TypeChecker {
     private final String methodOwnerType;
     private final MethodMatchers methodMatcher;
     private final int argumentIndex;
-    private boolean argumentIsACollection;
+    private final boolean argumentIsACollection;
     private final int parametrizedTypeIndex;
 
     private TypeChecker(String methodOwnerType, MethodMatchers methodMatcher, int argumentIndex, boolean argumentIsACollection, int parametrizedTypeIndex) {
diff --git a/java-checks/src/main/java/org/sonar/java/checks/ConstructorCallingOverridableCheck.java b/java-checks/src/main/java/org/sonar/java/checks/ConstructorCallingOverridableCheck.java
index 2513ad843a2..0e577572ab4 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/ConstructorCallingOverridableCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/ConstructorCallingOverridableCheck.java
@@ -52,7 +52,7 @@ public void visitNode(Tree tree) {
 
   private class ConstructorBodyVisitor extends BaseTreeVisitor {
 
-    private Symbol.TypeSymbol constructorType;
+    private final Symbol.TypeSymbol constructorType;
 
     public ConstructorBodyVisitor(Symbol.TypeSymbol constructorType) {
       this.constructorType = constructorType;
diff --git a/java-checks/src/main/java/org/sonar/java/checks/DiamondOperatorCheck.java b/java-checks/src/main/java/org/sonar/java/checks/DiamondOperatorCheck.java
index 4c9cdb8fe27..8c76579088b 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/DiamondOperatorCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/DiamondOperatorCheck.java
@@ -57,7 +57,7 @@
 public class DiamondOperatorCheck extends SubscriptionVisitor implements JavaVersionAwareVisitor {
 
   /** Nodes to check in Java 7. */
-  private static final Tree.Kind[] JAVA_7_KINDS = new Tree.Kind[] {
+  private static final Tree.Kind[] JAVA_7_KINDS = {
     Tree.Kind.VARIABLE,
     Tree.Kind.TYPE_CAST,
     Tree.Kind.RETURN_STATEMENT,
diff --git a/java-checks/src/main/java/org/sonar/java/checks/DoublePrefixOperatorCheck.java b/java-checks/src/main/java/org/sonar/java/checks/DoublePrefixOperatorCheck.java
index 1ddd4227c95..713dee466f9 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/DoublePrefixOperatorCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/DoublePrefixOperatorCheck.java
@@ -37,7 +37,7 @@ public List<Kind> nodesToVisit() {
     return Arrays.asList(Tree.Kind.LOGICAL_COMPLEMENT, Tree.Kind.BITWISE_COMPLEMENT, Tree.Kind.UNARY_PLUS, Tree.Kind.UNARY_MINUS);
   }
 
-  private Set<ExpressionTree> prefixSet = new HashSet<>();
+  private final Set<ExpressionTree> prefixSet = new HashSet<>();
 
   @Override
   public void setContext(JavaFileScannerContext context) {
diff --git a/java-checks/src/main/java/org/sonar/java/checks/HasNextCallingNextCheck.java b/java-checks/src/main/java/org/sonar/java/checks/HasNextCallingNextCheck.java
index 465df2e6ea8..68159b010e3 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/HasNextCallingNextCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/HasNextCallingNextCheck.java
@@ -34,7 +34,7 @@
 @Rule(key = "S1849")
 public class HasNextCallingNextCheck extends IssuableSubscriptionVisitor {
 
-  private HasNextBodyVisitor hasNextBodyVisitor = new HasNextBodyVisitor();
+  private final HasNextBodyVisitor hasNextBodyVisitor = new HasNextBodyVisitor();
 
   @Override
   public List<Kind> nodesToVisit() {
diff --git a/java-checks/src/main/java/org/sonar/java/checks/InnerStaticClassesCheck.java b/java-checks/src/main/java/org/sonar/java/checks/InnerStaticClassesCheck.java
index f383958a40a..4c748b92e16 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/InnerStaticClassesCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/InnerStaticClassesCheck.java
@@ -38,8 +38,8 @@
 public class InnerStaticClassesCheck extends BaseTreeVisitor implements JavaFileScanner {
 
   private JavaFileScannerContext context;
-  private Deque<Symbol> outerClasses = new LinkedList<>();
-  private Deque<Boolean> atLeastOneReference = new LinkedList<>();
+  private final Deque<Symbol> outerClasses = new LinkedList<>();
+  private final Deque<Boolean> atLeastOneReference = new LinkedList<>();
 
   @Override
   public void scanFile(final JavaFileScannerContext context) {
diff --git a/java-checks/src/main/java/org/sonar/java/checks/IterableIteratorCheck.java b/java-checks/src/main/java/org/sonar/java/checks/IterableIteratorCheck.java
index c51d9757ad8..29284c397d6 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/IterableIteratorCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/IterableIteratorCheck.java
@@ -64,7 +64,7 @@ public void visitNode(Tree tree) {
   }
 
   private static class ReturnThis extends BaseTreeVisitor {
-    private List<Tree> issueLocations = new ArrayList<>();
+    private final List<Tree> issueLocations = new ArrayList<>();
 
     @Override
     public void visitClass(ClassTree tree) {
diff --git a/java-checks/src/main/java/org/sonar/java/checks/LazyArgEvaluationCheck.java b/java-checks/src/main/java/org/sonar/java/checks/LazyArgEvaluationCheck.java
index 29bae332432..a09b4105499 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/LazyArgEvaluationCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/LazyArgEvaluationCheck.java
@@ -130,7 +130,7 @@ private static String[] testMethodNames(String[] lowerCaseNames) {
   }
 
   private JavaFileScannerContext context;
-  private Deque<Tree> treeStack = new ArrayDeque<>();
+  private final Deque<Tree> treeStack = new ArrayDeque<>();
   private boolean foundReturnStatementInsideLevelTest = false;
 
   @Override
diff --git a/java-checks/src/main/java/org/sonar/java/checks/MethodParametersOrderCheck.java b/java-checks/src/main/java/org/sonar/java/checks/MethodParametersOrderCheck.java
index a53d5ac5d7f..af91334a1d7 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/MethodParametersOrderCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/MethodParametersOrderCheck.java
@@ -43,7 +43,7 @@
 @Rule(key = "S2234")
 public class MethodParametersOrderCheck extends IssuableSubscriptionVisitor {
 
-  private Map<Symbol, ParametersList> parametersByMethod = new HashMap<>();
+  private final Map<Symbol, ParametersList> parametersByMethod = new HashMap<>();
 
   @Override
   public List<Tree.Kind> nodesToVisit() {
@@ -124,9 +124,9 @@ private static List<VariableTree> matchingTypesWrongOrder(ParametersList formalP
 
   private static class ParametersList {
 
-    private List<String> parameterNames;
-    private List<Type> parameterTypes;
-    private List<VariableTree> parameters;
+    private final List<String> parameterNames;
+    private final List<Type> parameterTypes;
+    private final List<VariableTree> parameters;
 
     public ParametersList(MethodTree methodTree) {
       parameterNames = new ArrayList<>();
diff --git a/java-checks/src/main/java/org/sonar/java/checks/ModifiersOrderCheck.java b/java-checks/src/main/java/org/sonar/java/checks/ModifiersOrderCheck.java
index f588de06576..7207d88ba76 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/ModifiersOrderCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/ModifiersOrderCheck.java
@@ -43,7 +43,7 @@
 @DeprecatedRuleKey(ruleKey = "ModifiersOrderCheck", repositoryKey = "squid")
 @Rule(key = "S1124")
 public class ModifiersOrderCheck extends IssuableSubscriptionVisitor {
-  private Set<Tree> alreadyReported = new HashSet<>();
+  private final Set<Tree> alreadyReported = new HashSet<>();
 
   @Override
   public void setContext(JavaFileScannerContext context) {
diff --git a/java-checks/src/main/java/org/sonar/java/checks/ModulusEqualityCheck.java b/java-checks/src/main/java/org/sonar/java/checks/ModulusEqualityCheck.java
index a9f4128e689..c8b0dc3d87a 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/ModulusEqualityCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/ModulusEqualityCheck.java
@@ -39,7 +39,7 @@
 @Rule(key = "S2197")
 public class ModulusEqualityCheck extends IssuableSubscriptionVisitor {
 
-  private Set<Symbol> methodParams = new HashSet<>();
+  private final Set<Symbol> methodParams = new HashSet<>();
 
   @Override
   public void leaveFile(JavaFileScannerContext context) {
diff --git a/java-checks/src/main/java/org/sonar/java/checks/NestedTryCatchCheck.java b/java-checks/src/main/java/org/sonar/java/checks/NestedTryCatchCheck.java
index 5b6194c8857..b3e7fbe282b 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/NestedTryCatchCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/NestedTryCatchCheck.java
@@ -33,7 +33,7 @@
 public class NestedTryCatchCheck extends BaseTreeVisitor implements JavaFileScanner {
 
   private JavaFileScannerContext context;
-  private Deque<Deque<Tree>> nestingLevel = new ArrayDeque<>();
+  private final Deque<Deque<Tree>> nestingLevel = new ArrayDeque<>();
 
   @Override
   public void scanFile(JavaFileScannerContext context) {
diff --git a/java-checks/src/main/java/org/sonar/java/checks/OperatorPrecedenceCheck.java b/java-checks/src/main/java/org/sonar/java/checks/OperatorPrecedenceCheck.java
index ae59b2313ce..e7f26d991bf 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/OperatorPrecedenceCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/OperatorPrecedenceCheck.java
@@ -73,7 +73,7 @@ public class OperatorPrecedenceCheck extends BaseTreeVisitor implements JavaFile
     Tree.Kind.UNSIGNED_RIGHT_SHIFT
     );
 
-  private static final Tree.Kind[] CONDITIONAL_EXCLUSIONS = new Tree.Kind[]{
+  private static final Tree.Kind[] CONDITIONAL_EXCLUSIONS = {
       Tree.Kind.METHOD_INVOCATION, Tree.Kind.IDENTIFIER, Tree.Kind.MEMBER_SELECT,
       Tree.Kind.PARENTHESIZED_EXPRESSION, Tree.Kind.TYPE_CAST, Tree.Kind.NEW_CLASS,
       Tree.Kind.ARRAY_ACCESS_EXPRESSION, Tree.Kind.NEW_ARRAY, Tree.Kind.METHOD_REFERENCE
@@ -90,8 +90,8 @@ public class OperatorPrecedenceCheck extends BaseTreeVisitor implements JavaFile
   }
 
   private JavaFileScannerContext context;
-  private Deque<Tree.Kind> stack = new LinkedList<>();
-  private Set<Integer> reportedLines = new HashSet<>();
+  private final Deque<Tree.Kind> stack = new LinkedList<>();
+  private final Set<Integer> reportedLines = new HashSet<>();
 
   private static void put(Iterable<Tree.Kind> firstSet, Iterable<Tree.Kind> secondSet) {
     for (Tree.Kind first : firstSet) {
diff --git a/java-checks/src/main/java/org/sonar/java/checks/OverwrittenKeyCheck.java b/java-checks/src/main/java/org/sonar/java/checks/OverwrittenKeyCheck.java
index f1b61f6aa56..9afdc81af3e 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/OverwrittenKeyCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/OverwrittenKeyCheck.java
@@ -106,7 +106,7 @@ private static class CollectionAndKey {
     private final Tree keyTree;
     private final Object key;
     private final boolean isArray;
-    private ExpressionTree rhs;
+    private final ExpressionTree rhs;
 
     private CollectionAndKey(Symbol collection, Tree keyTree, Object key, boolean isArray, @Nullable ExpressionTree expression) {
       this.collection = collection;
diff --git a/java-checks/src/main/java/org/sonar/java/checks/RedundantThrowsDeclarationCheck.java b/java-checks/src/main/java/org/sonar/java/checks/RedundantThrowsDeclarationCheck.java
index 542ddef75de..d5ad546f49b 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/RedundantThrowsDeclarationCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/RedundantThrowsDeclarationCheck.java
@@ -215,7 +215,7 @@ private static Set<Type> thrownExceptionsFromBody(MethodTree methodTree) {
   }
 
   private static class ThrownExceptionVisitor extends BaseTreeVisitor {
-    private Set<Type> thrownExceptions = new HashSet<>();
+    private final Set<Type> thrownExceptions = new HashSet<>();
     private boolean visitedUnknown = false;
     private boolean visitedOtherConstructor = false;
     private final MethodTree methodTree;
diff --git a/java-checks/src/main/java/org/sonar/java/checks/ShiftOnIntOrLongCheck.java b/java-checks/src/main/java/org/sonar/java/checks/ShiftOnIntOrLongCheck.java
index e06f7f14ba0..48ac3e0118e 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/ShiftOnIntOrLongCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/ShiftOnIntOrLongCheck.java
@@ -42,7 +42,7 @@
 @Rule(key = "S2183")
 public class ShiftOnIntOrLongCheck extends IssuableSubscriptionVisitor {
 
-  private List<Tree> shiftTrees = new ArrayList<>();
+  private final List<Tree> shiftTrees = new ArrayList<>();
 
   @Override
   public List<Kind> nodesToVisit() {
diff --git a/java-checks/src/main/java/org/sonar/java/checks/StaticFieldInitializationCheck.java b/java-checks/src/main/java/org/sonar/java/checks/StaticFieldInitializationCheck.java
index a309b145d23..e7e7c41c945 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/StaticFieldInitializationCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/StaticFieldInitializationCheck.java
@@ -36,10 +36,10 @@
 @Rule(key = "S2444")
 public class StaticFieldInitializationCheck extends AbstractInSynchronizeChecker {
 
-  private Deque<Boolean> classWithSynchronizedMethod = new LinkedList<>();
-  private Deque<Boolean> withinStaticInitializer = new LinkedList<>();
-  private Deque<Boolean> methodUsesLocks = new LinkedList<>();
-  private MethodMatchers locks = MethodMatchers.create()
+  private final Deque<Boolean> classWithSynchronizedMethod = new LinkedList<>();
+  private final Deque<Boolean> withinStaticInitializer = new LinkedList<>();
+  private final Deque<Boolean> methodUsesLocks = new LinkedList<>();
+  private final MethodMatchers locks = MethodMatchers.create()
     .ofTypes("java.util.concurrent.locks.Lock")
     .names("lock", "tryLock")
     .addWithoutParametersMatcher()
diff --git a/java-checks/src/main/java/org/sonar/java/checks/StaticFieldUpateCheck.java b/java-checks/src/main/java/org/sonar/java/checks/StaticFieldUpateCheck.java
index bc63f291098..23a05294663 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/StaticFieldUpateCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/StaticFieldUpateCheck.java
@@ -40,13 +40,13 @@
 @Rule(key = "S2696")
 public class StaticFieldUpateCheck extends AbstractInSynchronizeChecker {
 
-  private static final Kind[] UNARY_EXPRESSIONS = new Kind[]{
+  private static final Kind[] UNARY_EXPRESSIONS = {
     Kind.POSTFIX_DECREMENT,
     Kind.POSTFIX_INCREMENT,
     Kind.PREFIX_DECREMENT,
     Kind.PREFIX_INCREMENT};
 
-  private Deque<Boolean> withinStaticMethod = new LinkedList<>();
+  private final Deque<Boolean> withinStaticMethod = new LinkedList<>();
 
   @Override
   public List<Kind> nodesToVisit() {
diff --git a/java-checks/src/main/java/org/sonar/java/checks/StaticMethodCheck.java b/java-checks/src/main/java/org/sonar/java/checks/StaticMethodCheck.java
index 58e23ee3c4c..59a35d7551a 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/StaticMethodCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/StaticMethodCheck.java
@@ -87,7 +87,7 @@ public class StaticMethodCheck extends BaseTreeVisitor implements JavaFileScanne
   };
 
   private JavaFileScannerContext context;
-  private Deque<MethodReference> methodReferences = new LinkedList<>();
+  private final Deque<MethodReference> methodReferences = new LinkedList<>();
 
   @Override
   public void scanFile(JavaFileScannerContext context) {
diff --git a/java-checks/src/main/java/org/sonar/java/checks/StringConcatenationInLoopCheck.java b/java-checks/src/main/java/org/sonar/java/checks/StringConcatenationInLoopCheck.java
index f930199df5e..eeebe751581 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/StringConcatenationInLoopCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/StringConcatenationInLoopCheck.java
@@ -42,7 +42,7 @@
 public class StringConcatenationInLoopCheck extends BaseTreeVisitor implements JavaFileScanner {
 
   private JavaFileScannerContext context;
-  private Deque<Tree> loopLevel = new LinkedList<>();
+  private final Deque<Tree> loopLevel = new LinkedList<>();
 
   @Override
   public void scanFile(JavaFileScannerContext context) {
diff --git a/java-checks/src/main/java/org/sonar/java/checks/SunPackagesUsedCheck.java b/java-checks/src/main/java/org/sonar/java/checks/SunPackagesUsedCheck.java
index 818b587dae3..a3e400d7978 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/SunPackagesUsedCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/SunPackagesUsedCheck.java
@@ -30,7 +30,7 @@
 @Rule(key = "S1191")
 public class SunPackagesUsedCheck extends BaseTreeVisitor implements JavaFileScanner {
 
-  private List<Tree> reportedTrees = new ArrayList<>();
+  private final List<Tree> reportedTrees = new ArrayList<>();
 
   private static final String DEFAULT_EXCLUDE = "";
 
diff --git a/java-checks/src/main/java/org/sonar/java/checks/SynchronizedClassUsageCheck.java b/java-checks/src/main/java/org/sonar/java/checks/SynchronizedClassUsageCheck.java
index eb55e3cb70c..5b060dc5afe 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/SynchronizedClassUsageCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/SynchronizedClassUsageCheck.java
@@ -113,7 +113,7 @@ private static boolean isMethodFromJavaPackage(String fqn) {
 
   private class DeprecatedTypeVisitor extends BaseTreeVisitor {
 
-    private Deque<Set<String>> overridingMethodTypes = new ArrayDeque<>();
+    private final Deque<Set<String>> overridingMethodTypes = new ArrayDeque<>();
 
     @Override
     public void visitClass(ClassTree tree) {
diff --git a/java-checks/src/main/java/org/sonar/java/checks/ThisExposedFromConstructorCheck.java b/java-checks/src/main/java/org/sonar/java/checks/ThisExposedFromConstructorCheck.java
index 42521049777..45f5d2edd5c 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/ThisExposedFromConstructorCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/ThisExposedFromConstructorCheck.java
@@ -47,7 +47,7 @@ public void visitNode(Tree tree) {
   }
 
   private class ConstructorBodyVisitor extends BaseTreeVisitor {
-    private Symbol owner;
+    private final Symbol owner;
 
     public ConstructorBodyVisitor(Symbol owner) {
       this.owner = owner;
diff --git a/java-checks/src/main/java/org/sonar/java/checks/ThrowCheckedExceptionCheck.java b/java-checks/src/main/java/org/sonar/java/checks/ThrowCheckedExceptionCheck.java
index a847c524ea1..cde0a73c385 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/ThrowCheckedExceptionCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/ThrowCheckedExceptionCheck.java
@@ -30,7 +30,7 @@
 @Rule(key = "S1162")
 public class ThrowCheckedExceptionCheck extends IssuableSubscriptionVisitor {
 
-  private Deque<MethodTree> methods = new LinkedList<>();
+  private final Deque<MethodTree> methods = new LinkedList<>();
 
   @Override
   public List<Tree.Kind> nodesToVisit() {
diff --git a/java-checks/src/main/java/org/sonar/java/checks/ToStringUsingBoxingCheck.java b/java-checks/src/main/java/org/sonar/java/checks/ToStringUsingBoxingCheck.java
index 89378dead25..ce3fea57b82 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/ToStringUsingBoxingCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/ToStringUsingBoxingCheck.java
@@ -37,7 +37,7 @@
 @Rule(key = "S1158")
 public class ToStringUsingBoxingCheck extends IssuableSubscriptionVisitor {
 
-  private static final String[] PRIMITIVE_WRAPPERS = new String[]{
+  private static final String[] PRIMITIVE_WRAPPERS = {
     "java.lang.Byte",
     "java.lang.Character",
     "java.lang.Short",
diff --git a/java-checks/src/main/java/org/sonar/java/checks/WaitInWhileLoopCheck.java b/java-checks/src/main/java/org/sonar/java/checks/WaitInWhileLoopCheck.java
index a872fe937c4..3ba31072429 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/WaitInWhileLoopCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/WaitInWhileLoopCheck.java
@@ -33,7 +33,7 @@
 @Rule(key = "S2274")
 public class WaitInWhileLoopCheck extends AbstractMethodDetection {
 
-  private Deque<Boolean> inWhileLoop = new LinkedList<>();
+  private final Deque<Boolean> inWhileLoop = new LinkedList<>();
 
   @Override
   protected void clearState() {
diff --git a/java-checks/src/main/java/org/sonar/java/checks/security/ExcessiveContentRequestCheck.java b/java-checks/src/main/java/org/sonar/java/checks/security/ExcessiveContentRequestCheck.java
index 2914eb3335b..9f2a133f580 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/security/ExcessiveContentRequestCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/security/ExcessiveContentRequestCheck.java
@@ -133,7 +133,7 @@ public class ExcessiveContentRequestCheck extends IssuableSubscriptionVisitor im
   private final List<AnalyzerMessage> multipartConstructorIssues = new ArrayList<>();
   private boolean sizeSetSomewhere = false;
 
-  private Set<String> filesCached = new HashSet<>();
+  private final Set<String> filesCached = new HashSet<>();
 
   private boolean currentFileSetsMaximumSize = false;
   private boolean currentFileInstantiates = false;
diff --git a/java-checks/src/main/java/org/sonar/java/checks/security/VerifiedServerHostnamesCheck.java b/java-checks/src/main/java/org/sonar/java/checks/security/VerifiedServerHostnamesCheck.java
index 2c00dc0641c..384d8cedf15 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/security/VerifiedServerHostnamesCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/security/VerifiedServerHostnamesCheck.java
@@ -192,7 +192,7 @@ private static boolean isNotFalse(ExpressionTree expression) {
 
   private static class MethodBodyApacheVisitor extends BaseTreeVisitor {
     private boolean isSecured = false;
-    private Symbol variable;
+    private final Symbol variable;
 
     private static final MethodMatchers SET_SSL_CHECK_SERVER_ID = MethodMatchers.create()
       .ofSubTypes(APACHE_EMAIL)
@@ -215,7 +215,7 @@ public void visitMethodInvocation(MethodInvocationTree mit) {
 
   private static class MethodBodyHashtableVisitor extends BaseTreeVisitor {
     private boolean isSecured = false;
-    private Symbol variable;
+    private final Symbol variable;
 
     MethodBodyHashtableVisitor(@Nullable Symbol variable) {
       this.variable = variable;
diff --git a/java-checks/src/main/java/org/sonar/java/checks/security/XxeActiveMQCheck.java b/java-checks/src/main/java/org/sonar/java/checks/security/XxeActiveMQCheck.java
index bb2f52cf856..de6a6247de1 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/security/XxeActiveMQCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/security/XxeActiveMQCheck.java
@@ -80,7 +80,7 @@ private static class MethodBodyVisitor extends BaseTreeVisitor {
     private boolean hasTrustAllPackages = false;
     private boolean callArgumentsOfSetTrustedPackages = false;
 
-    private Symbol variable;
+    private final Symbol variable;
 
     MethodBodyVisitor(@Nullable Symbol variable) {
       this.variable = variable;
diff --git a/java-checks/src/main/java/org/sonar/java/checks/serialization/SerializableFieldInSerializableClassCheck.java b/java-checks/src/main/java/org/sonar/java/checks/serialization/SerializableFieldInSerializableClassCheck.java
index 16bac0f3e40..c5d608cfcd7 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/serialization/SerializableFieldInSerializableClassCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/serialization/SerializableFieldInSerializableClassCheck.java
@@ -49,7 +49,7 @@ public class SerializableFieldInSerializableClassCheck extends IssuableSubscript
   private static final String JAVAX_INJECT = "javax.inject.Inject";
   private static final String JAKARTA_INJECT = "jakarta.inject.Inject";
 
-  private static final String[] EXCLUDED_ANNOTATIONS = new String[]{
+  private static final String[] EXCLUDED_ANNOTATIONS = {
     "jakarta.annotation.Resource",
     "javax.annotation.Resource",
     "javax.ejb.EJB",
diff --git a/java-checks/src/main/java/org/sonar/java/checks/synchronization/DoubleCheckedLockingCheck.java b/java-checks/src/main/java/org/sonar/java/checks/synchronization/DoubleCheckedLockingCheck.java
index fb0fd4ae35f..c68b7f11d3d 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/synchronization/DoubleCheckedLockingCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/synchronization/DoubleCheckedLockingCheck.java
@@ -53,8 +53,8 @@
 @Rule(key = "S2168")
 public class DoubleCheckedLockingCheck extends IssuableSubscriptionVisitor {
 
-  private Deque<IfFieldEqNull> ifFieldStack = new LinkedList<>();
-  private Deque<CriticalSection> synchronizedStmtStack = new LinkedList<>();
+  private final Deque<IfFieldEqNull> ifFieldStack = new LinkedList<>();
+  private final Deque<CriticalSection> synchronizedStmtStack = new LinkedList<>();
   private boolean methodIsSynchronized;
 
   @Override
@@ -165,7 +165,7 @@ private static boolean thenStmtInitializeField(StatementTree statementTree, Symb
   private static class AssignmentVisitor extends BaseTreeVisitor {
 
     private boolean assignmentToField;
-    private Symbol field;
+    private final Symbol field;
 
     AssignmentVisitor(Symbol field) {
       this.field = field;
diff --git a/java-checks/src/main/java/org/sonar/java/checks/synchronization/TwoLocksWaitCheck.java b/java-checks/src/main/java/org/sonar/java/checks/synchronization/TwoLocksWaitCheck.java
index 1b3ca2379a5..c517a4ec469 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/synchronization/TwoLocksWaitCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/synchronization/TwoLocksWaitCheck.java
@@ -43,7 +43,7 @@ public class TwoLocksWaitCheck extends IssuableSubscriptionVisitor {
 
   private static final MethodMatchers WAIT_MATCHER = MethodMatchers.create().ofAnyType().names("wait").addWithoutParametersMatcher().build();
 
-  private Deque<Counter> synchronizedStack = new LinkedList<>();
+  private final Deque<Counter> synchronizedStack = new LinkedList<>();
 
   @Override
   public List<Tree.Kind> nodesToVisit() {
@@ -85,7 +85,7 @@ private static List<JavaFileScannerContext.Location> flowFromTree(Tree tree) {
   private class MethodInvocationVisitor extends BaseTreeVisitor {
 
     private final MethodMatchers methodMatcher;
-    private Stream.Builder<MethodInvocationTree> matchedMethods = Stream.builder();
+    private final Stream.Builder<MethodInvocationTree> matchedMethods = Stream.builder();
 
     private MethodInvocationVisitor(MethodMatchers methodMatcher) {
       this.methodMatcher = methodMatcher;
@@ -123,7 +123,7 @@ private Stream<MethodInvocationTree> matchedMethods() {
 
   private static class SynchronizedKeywordVisitor extends BaseTreeVisitor {
 
-    private Stream.Builder<SyntaxToken> synchronizedKeywords = Stream.builder();
+    private final Stream.Builder<SyntaxToken> synchronizedKeywords = Stream.builder();
 
     @Override
     public void visitSynchronizedStatement(SynchronizedStatementTree tree) {
diff --git a/java-checks/src/main/java/org/sonar/java/checks/tests/AssertionsInTestsCheck.java b/java-checks/src/main/java/org/sonar/java/checks/tests/AssertionsInTestsCheck.java
index bc6779a851e..0b3497f51e0 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/tests/AssertionsInTestsCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/tests/AssertionsInTestsCheck.java
@@ -246,7 +246,7 @@ private static boolean expectAssertion(MethodTree methodTree) {
   }
 
   private class AssertionVisitor extends AbstractAssertionVisitor {
-    private MethodMatchers customMethodsMatcher;
+    private final MethodMatchers customMethodsMatcher;
 
     private AssertionVisitor(MethodMatchers customMethodsMatcher) {
       this.customMethodsMatcher = customMethodsMatcher;
diff --git a/java-checks/src/main/java/org/sonar/java/checks/tests/ExpectedExceptionCheck.java b/java-checks/src/main/java/org/sonar/java/checks/tests/ExpectedExceptionCheck.java
index 99a9cfe0829..7262de048c1 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/tests/ExpectedExceptionCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/tests/ExpectedExceptionCheck.java
@@ -62,8 +62,8 @@ protected void onMethodInvocationFound(MethodInvocationTree mit) {
 
   private static class AssertionCollector extends BaseTreeVisitor {
 
-    private int collectAfterLine;
-    private List<Location> assertions = new ArrayList<>();
+    private final int collectAfterLine;
+    private final List<Location> assertions = new ArrayList<>();
 
     public AssertionCollector(int collectAfterLine) {
       this.collectAfterLine = collectAfterLine;
diff --git a/java-checks/src/main/java/org/sonar/java/checks/tests/JUnit5SilentlyIgnoreClassAndMethodCheck.java b/java-checks/src/main/java/org/sonar/java/checks/tests/JUnit5SilentlyIgnoreClassAndMethodCheck.java
index 3d3a8d055aa..a3085d48877 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/tests/JUnit5SilentlyIgnoreClassAndMethodCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/tests/JUnit5SilentlyIgnoreClassAndMethodCheck.java
@@ -130,7 +130,7 @@ private void raiseIssueOnNonCompliantReturnType(MethodTree methodTree) {
   }
 
   static final class ReturnStatementVisitor extends BaseTreeVisitor {
-    private List<ReturnStatementTree> returnStatementTrees = new ArrayList<>();
+    private final List<ReturnStatementTree> returnStatementTrees = new ArrayList<>();
 
     ReturnStatementVisitor(MethodTree methodTree) {
       scan(methodTree);
diff --git a/java-frontend/src/main/java/org/sonar/java/JavaFilesCache.java b/java-frontend/src/main/java/org/sonar/java/JavaFilesCache.java
index 00879f8ff63..778540a840e 100644
--- a/java-frontend/src/main/java/org/sonar/java/JavaFilesCache.java
+++ b/java-frontend/src/main/java/org/sonar/java/JavaFilesCache.java
@@ -33,10 +33,10 @@
 
 public class JavaFilesCache extends BaseTreeVisitor implements JavaFileScanner {
 
-  private Set<String> classNames = new HashSet<>();
-  private Deque<String> currentClassKey = new LinkedList<>();
-  private Deque<Tree> parent = new LinkedList<>();
-  private Deque<Integer> anonymousInnerClassCounter = new LinkedList<>();
+  private final Set<String> classNames = new HashSet<>();
+  private final Deque<String> currentClassKey = new LinkedList<>();
+  private final Deque<Tree> parent = new LinkedList<>();
+  private final Deque<Integer> anonymousInnerClassCounter = new LinkedList<>();
   private String currentPackage;
 
   public Set<String> getClassNames() {
diff --git a/java-frontend/src/main/java/org/sonar/java/ast/visitors/CommentLinesVisitor.java b/java-frontend/src/main/java/org/sonar/java/ast/visitors/CommentLinesVisitor.java
index 67376e3179b..aedd090552f 100644
--- a/java-frontend/src/main/java/org/sonar/java/ast/visitors/CommentLinesVisitor.java
+++ b/java-frontend/src/main/java/org/sonar/java/ast/visitors/CommentLinesVisitor.java
@@ -32,9 +32,9 @@
 
 public class CommentLinesVisitor extends SubscriptionVisitor {
 
-  private Set<Integer> comments = new HashSet<>();
-  private Set<Integer> noSonarLines = new HashSet<>();
-  private Map<Path, Set<SyntaxTrivia>> syntaxTrivia = new HashMap<>();
+  private final Set<Integer> comments = new HashSet<>();
+  private final Set<Integer> noSonarLines = new HashSet<>();
+  private final Map<Path, Set<SyntaxTrivia>> syntaxTrivia = new HashMap<>();
   private boolean seenFirstToken;
 
   @Override
diff --git a/java-frontend/src/main/java/org/sonar/java/ast/visitors/ComplexityVisitor.java b/java-frontend/src/main/java/org/sonar/java/ast/visitors/ComplexityVisitor.java
index 938fe358915..71895dcfccf 100644
--- a/java-frontend/src/main/java/org/sonar/java/ast/visitors/ComplexityVisitor.java
+++ b/java-frontend/src/main/java/org/sonar/java/ast/visitors/ComplexityVisitor.java
@@ -35,7 +35,7 @@
 
 public class ComplexityVisitor extends BaseTreeVisitor {
 
-  private List<Tree> blame = new ArrayList<>();
+  private final List<Tree> blame = new ArrayList<>();
   private Tree root;
   private static final String DEFAULT_KEYWORD = JavaKeyword.DEFAULT.getValue();
 
diff --git a/java-frontend/src/main/java/org/sonar/java/ast/visitors/LinesOfCodeVisitor.java b/java-frontend/src/main/java/org/sonar/java/ast/visitors/LinesOfCodeVisitor.java
index 87aee79057d..e29a94e2935 100644
--- a/java-frontend/src/main/java/org/sonar/java/ast/visitors/LinesOfCodeVisitor.java
+++ b/java-frontend/src/main/java/org/sonar/java/ast/visitors/LinesOfCodeVisitor.java
@@ -28,7 +28,7 @@
 
 public class LinesOfCodeVisitor extends SubscriptionVisitor{
 
-  private Set<Integer> lines = new HashSet<>();
+  private final Set<Integer> lines = new HashSet<>();
 
   public int linesOfCode(Tree tree) {
     lines.clear();
diff --git a/java-frontend/src/main/java/org/sonar/java/ast/visitors/StatementVisitor.java b/java-frontend/src/main/java/org/sonar/java/ast/visitors/StatementVisitor.java
index 288af25d3bb..6c872602356 100644
--- a/java-frontend/src/main/java/org/sonar/java/ast/visitors/StatementVisitor.java
+++ b/java-frontend/src/main/java/org/sonar/java/ast/visitors/StatementVisitor.java
@@ -44,7 +44,7 @@
 
 public class StatementVisitor extends BaseTreeVisitor {
   private int statements;
-  private Set<Tree> variableTypes = new HashSet<>();
+  private final Set<Tree> variableTypes = new HashSet<>();
 
   public int numberOfStatements(Tree tree) {
     statements = 0;
diff --git a/java-frontend/src/main/java/org/sonar/java/caching/JavaWriteCacheImpl.java b/java-frontend/src/main/java/org/sonar/java/caching/JavaWriteCacheImpl.java
index b65c4fe4fc4..48c1a7108c6 100644
--- a/java-frontend/src/main/java/org/sonar/java/caching/JavaWriteCacheImpl.java
+++ b/java-frontend/src/main/java/org/sonar/java/caching/JavaWriteCacheImpl.java
@@ -24,7 +24,7 @@
 import org.sonarsource.performance.measure.PerformanceMeasure;
 
 public class JavaWriteCacheImpl implements JavaWriteCache {
-  private WriteCache writeCache;
+  private final WriteCache writeCache;
 
   public JavaWriteCacheImpl(WriteCache writeCache) {
     this.writeCache = writeCache;
diff --git a/java-frontend/src/main/java/org/sonar/java/cfg/CFG.java b/java-frontend/src/main/java/org/sonar/java/cfg/CFG.java
index d885c120b89..0ad03387eeb 100644
--- a/java-frontend/src/main/java/org/sonar/java/cfg/CFG.java
+++ b/java-frontend/src/main/java/org/sonar/java/cfg/CFG.java
@@ -131,8 +131,8 @@ public void addCatch(Type type, Block catchBlock) {
   }
 
   private String pendingLabel = null;
-  private Map<String, Block> labelsBreakTarget = new HashMap<>();
-  private Map<String, Block> labelsContinueTarget = new HashMap<>();
+  private final Map<String, Block> labelsBreakTarget = new HashMap<>();
+  private final Map<String, Block> labelsContinueTarget = new HashMap<>();
 
   private CFG(List<? extends Tree> trees, @Nullable MethodTree tree) {
     if (tree != null) {
diff --git a/java-frontend/src/main/java/org/sonar/java/matcher/MethodMatchersList.java b/java-frontend/src/main/java/org/sonar/java/matcher/MethodMatchersList.java
index fac6c759185..e50dcac9b46 100644
--- a/java-frontend/src/main/java/org/sonar/java/matcher/MethodMatchersList.java
+++ b/java-frontend/src/main/java/org/sonar/java/matcher/MethodMatchersList.java
@@ -28,7 +28,7 @@
 
 public class MethodMatchersList implements MethodMatchers {
 
-  private List<? extends MethodMatchers> matchers;
+  private final List<? extends MethodMatchers> matchers;
 
   public MethodMatchersList(List<? extends MethodMatchers> matchers) {
     this.matchers = new ArrayList<>(matchers);
diff --git a/java-frontend/src/main/java/org/sonar/java/model/VisitorsBridge.java b/java-frontend/src/main/java/org/sonar/java/model/VisitorsBridge.java
index cbee2624114..bed0a6217a9 100644
--- a/java-frontend/src/main/java/org/sonar/java/model/VisitorsBridge.java
+++ b/java-frontend/src/main/java/org/sonar/java/model/VisitorsBridge.java
@@ -392,8 +392,8 @@ public void endOfAnalysis() {
   }
 
   private class IssuableSubscriptionVisitorsRunner implements JavaFileScanner, EndOfAnalysis {
-    private EnumMap<Tree.Kind, List<SubscriptionVisitor>> checks;
-    private List<SubscriptionVisitor> subscriptionVisitors;
+    private final EnumMap<Tree.Kind, List<SubscriptionVisitor>> checks;
+    private final List<SubscriptionVisitor> subscriptionVisitors;
 
     IssuableSubscriptionVisitorsRunner() {
       checks = new EnumMap<>(Tree.Kind.class);
diff --git a/java-frontend/src/main/java/org/sonar/java/model/declaration/VariableTreeImpl.java b/java-frontend/src/main/java/org/sonar/java/model/declaration/VariableTreeImpl.java
index baab14748aa..e46d74b113a 100644
--- a/java-frontend/src/main/java/org/sonar/java/model/declaration/VariableTreeImpl.java
+++ b/java-frontend/src/main/java/org/sonar/java/model/declaration/VariableTreeImpl.java
@@ -42,7 +42,7 @@
 public class VariableTreeImpl extends JavaTree implements VariableTree {
   private ModifiersTree modifiers;
   private TypeTree type;
-  private IdentifierTree simpleName;
+  private final IdentifierTree simpleName;
   @Nullable
   private SyntaxToken equalToken;
   @Nullable
diff --git a/java-frontend/src/main/java/org/sonar/java/model/expression/MemberSelectExpressionTreeImpl.java b/java-frontend/src/main/java/org/sonar/java/model/expression/MemberSelectExpressionTreeImpl.java
index 42a2bc7c800..026c44c84bc 100644
--- a/java-frontend/src/main/java/org/sonar/java/model/expression/MemberSelectExpressionTreeImpl.java
+++ b/java-frontend/src/main/java/org/sonar/java/model/expression/MemberSelectExpressionTreeImpl.java
@@ -33,9 +33,9 @@
 
 public class MemberSelectExpressionTreeImpl extends AssessableExpressionTree implements MemberSelectExpressionTree, JavaTree.AnnotatedTypeTree {
 
-  private ExpressionTree expression;
+  private final ExpressionTree expression;
 
-  private InternalSyntaxToken dotToken;
+  private final InternalSyntaxToken dotToken;
   private final IdentifierTree identifier;
   private List<AnnotationTree> annotations;
 
diff --git a/java-frontend/src/main/java/org/sonar/java/model/expression/MethodReferenceTreeImpl.java b/java-frontend/src/main/java/org/sonar/java/model/expression/MethodReferenceTreeImpl.java
index c5918703817..f88d25018ea 100644
--- a/java-frontend/src/main/java/org/sonar/java/model/expression/MethodReferenceTreeImpl.java
+++ b/java-frontend/src/main/java/org/sonar/java/model/expression/MethodReferenceTreeImpl.java
@@ -32,8 +32,8 @@
 
 public class MethodReferenceTreeImpl extends AssessableExpressionTree implements MethodReferenceTree {
 
-  private Tree expression;
-  private SyntaxToken doubleColon;
+  private final Tree expression;
+  private final SyntaxToken doubleColon;
   private IdentifierTree method;
   private TypeArguments typeArgument;
 
diff --git a/java-frontend/src/main/java/org/sonar/java/model/expression/NewClassTreeImpl.java b/java-frontend/src/main/java/org/sonar/java/model/expression/NewClassTreeImpl.java
index a98099c072a..cbd2a572b70 100644
--- a/java-frontend/src/main/java/org/sonar/java/model/expression/NewClassTreeImpl.java
+++ b/java-frontend/src/main/java/org/sonar/java/model/expression/NewClassTreeImpl.java
@@ -47,7 +47,7 @@ public class NewClassTreeImpl extends AssessableExpressionTree implements NewCla
   private SyntaxToken newKeyword;
   @Nullable
   private TypeArguments typeArguments;
-  private TypeTree identifier;
+  private final TypeTree identifier;
   private final Arguments arguments;
   @Nullable
   private final ClassTree classBody;
diff --git a/java-frontend/src/main/java/org/sonar/java/model/statement/IfStatementTreeImpl.java b/java-frontend/src/main/java/org/sonar/java/model/statement/IfStatementTreeImpl.java
index e4ffff7ebb8..0f2656cd746 100644
--- a/java-frontend/src/main/java/org/sonar/java/model/statement/IfStatementTreeImpl.java
+++ b/java-frontend/src/main/java/org/sonar/java/model/statement/IfStatementTreeImpl.java
@@ -32,11 +32,11 @@
 
 public class IfStatementTreeImpl extends JavaTree implements IfStatementTree {
 
-  private InternalSyntaxToken ifKeyword;
-  private InternalSyntaxToken openParenToken;
-  private ExpressionTree condition;
-  private InternalSyntaxToken closeParenToken;
-  private StatementTree thenStatement;
+  private final InternalSyntaxToken ifKeyword;
+  private final InternalSyntaxToken openParenToken;
+  private final ExpressionTree condition;
+  private final InternalSyntaxToken closeParenToken;
+  private final StatementTree thenStatement;
   @Nullable
   private final InternalSyntaxToken elseKeyword;
   @Nullable
diff --git a/java-frontend/src/main/java/org/sonar/java/model/statement/StaticInitializerTreeImpl.java b/java-frontend/src/main/java/org/sonar/java/model/statement/StaticInitializerTreeImpl.java
index f71270cf892..39c21d0bdaf 100644
--- a/java-frontend/src/main/java/org/sonar/java/model/statement/StaticInitializerTreeImpl.java
+++ b/java-frontend/src/main/java/org/sonar/java/model/statement/StaticInitializerTreeImpl.java
@@ -26,7 +26,7 @@
 
 public class StaticInitializerTreeImpl extends BlockTreeImpl implements StaticInitializerTree {
 
-  private SyntaxToken staticKeyword;
+  private final SyntaxToken staticKeyword;
 
   public StaticInitializerTreeImpl(InternalSyntaxToken staticKeyword, InternalSyntaxToken openBraceToken, List<StatementTree> body, InternalSyntaxToken closeBraceToken) {
     super(Tree.Kind.STATIC_INITIALIZER, openBraceToken, body, closeBraceToken);
diff --git a/java-frontend/src/main/java/org/sonar/java/model/statement/TryStatementTreeImpl.java b/java-frontend/src/main/java/org/sonar/java/model/statement/TryStatementTreeImpl.java
index 88da585f929..4b5563f8a0f 100644
--- a/java-frontend/src/main/java/org/sonar/java/model/statement/TryStatementTreeImpl.java
+++ b/java-frontend/src/main/java/org/sonar/java/model/statement/TryStatementTreeImpl.java
@@ -32,16 +32,16 @@
 
 public class TryStatementTreeImpl extends JavaTree implements TryStatementTree {
 
-  private InternalSyntaxToken tryToken;
+  private final InternalSyntaxToken tryToken;
 
   @Nullable
   private InternalSyntaxToken openParenToken;
-  private ListTree<Tree> resources;
+  private final ListTree<Tree> resources;
   @Nullable
   private InternalSyntaxToken closeParenToken;
 
-  private BlockTree block;
-  private List<CatchTree> catches;
+  private final BlockTree block;
+  private final List<CatchTree> catches;
 
   @Nullable
   private final InternalSyntaxToken finallyKeyword;
diff --git a/java-frontend/src/main/java/org/sonar/java/testing/VisitorsBridgeForTests.java b/java-frontend/src/main/java/org/sonar/java/testing/VisitorsBridgeForTests.java
index 80a0ccf05c9..19d06d56eb3 100644
--- a/java-frontend/src/main/java/org/sonar/java/testing/VisitorsBridgeForTests.java
+++ b/java-frontend/src/main/java/org/sonar/java/testing/VisitorsBridgeForTests.java
@@ -39,7 +39,7 @@
 
 public class VisitorsBridgeForTests extends VisitorsBridge {
 
-  private List<JavaFileScannerContextForTests> testContexts = new ArrayList<>();
+  private final List<JavaFileScannerContextForTests> testContexts = new ArrayList<>();
   private JavaFileScannerContextForTests moduleContext;
   private final boolean enableSemantic;
 
diff --git a/java-frontend/src/test/java/org/sonar/java/ast/visitors/FileLinesVisitorTest.java b/java-frontend/src/test/java/org/sonar/java/ast/visitors/FileLinesVisitorTest.java
index 47665bbdaa7..ef0e1db4fb1 100644
--- a/java-frontend/src/test/java/org/sonar/java/ast/visitors/FileLinesVisitorTest.java
+++ b/java-frontend/src/test/java/org/sonar/java/ast/visitors/FileLinesVisitorTest.java
@@ -76,7 +76,7 @@ void lines_of_code_data() {
   void executable_lines_should_be_counted() {
     FileLinesContext context = mock(FileLinesContext.class);
     checkLines("ExecutableLines.java", context);
-    int[] expected = new int[] {0, 0, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 1, 1,
+    int[] expected = {0, 0, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 1, 1,
       0, 1, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0};
     assertThat(expected).hasSize(56);
     for (int i = 0; i < expected.length; i++) {
diff --git a/java-frontend/src/test/java/org/sonar/java/caching/ContentHashCacheTest.java b/java-frontend/src/test/java/org/sonar/java/caching/ContentHashCacheTest.java
index 2724e0f240e..65710fd7a9f 100644
--- a/java-frontend/src/test/java/org/sonar/java/caching/ContentHashCacheTest.java
+++ b/java-frontend/src/test/java/org/sonar/java/caching/ContentHashCacheTest.java
@@ -63,7 +63,7 @@ void hasSameHashCached_returns_true_when_content_hash_file_is_in_read_cache() th
   @Test
   void hasSameHashCached_returns_false_when_content_hash_file_is_not_in_read_cache_with_proper_logging() {
     String cacheMissMessage = "Could not find key java:contentHash:MD5:" + inputFile.key() + " in the cache";
-    String[] traceMessages = new String[]{
+    String[] traceMessages = {
       "Reading cache for the file " + inputFile.key(),
       "Writing to the cache for file " + inputFile.key()
     };
diff --git a/java-frontend/src/test/java/org/sonar/java/cfg/CFGTest.java b/java-frontend/src/test/java/org/sonar/java/cfg/CFGTest.java
index 9a8940ab94f..543bd51f429 100644
--- a/java-frontend/src/test/java/org/sonar/java/cfg/CFGTest.java
+++ b/java-frontend/src/test/java/org/sonar/java/cfg/CFGTest.java
@@ -167,8 +167,8 @@ private void checkLinkedBlocks(int id, String type, List<Block> blocks, Set<Bloc
 
   private static class BlockChecker {
 
-    private int[] successorIDs = new int[] {};
-    private int[] exceptionsIDs = new int[] {};
+    private int[] successorIDs = {};
+    private int[] exceptionsIDs = {};
     private final List<ElementChecker> checkers = new ArrayList<>();
     private TerminatorChecker terminatorChecker;
     private int ifTrue = -1;
diff --git a/java-surefire/src/main/java/org/sonar/plugins/surefire/StaxParser.java b/java-surefire/src/main/java/org/sonar/plugins/surefire/StaxParser.java
index 3224a9d4914..68c229e4601 100644
--- a/java-surefire/src/main/java/org/sonar/plugins/surefire/StaxParser.java
+++ b/java-surefire/src/main/java/org/sonar/plugins/surefire/StaxParser.java
@@ -31,8 +31,8 @@
 
 public class StaxParser {
 
-  private SMInputFactory inf;
-  private SurefireStaxHandler streamHandler;
+  private final SMInputFactory inf;
+  private final SurefireStaxHandler streamHandler;
 
   public StaxParser(UnitTestIndex index) {
     this.streamHandler = new SurefireStaxHandler(index);
diff --git a/java-surefire/src/main/java/org/sonar/plugins/surefire/data/UnitTestIndex.java b/java-surefire/src/main/java/org/sonar/plugins/surefire/data/UnitTestIndex.java
index 13bc9183880..eb299b7f0a0 100644
--- a/java-surefire/src/main/java/org/sonar/plugins/surefire/data/UnitTestIndex.java
+++ b/java-surefire/src/main/java/org/sonar/plugins/surefire/data/UnitTestIndex.java
@@ -26,7 +26,7 @@
  */
 public class UnitTestIndex {
 
-  private Map<String, UnitTestClassReport> indexByClassname;
+  private final Map<String, UnitTestClassReport> indexByClassname;
 
   public UnitTestIndex() {
     this.indexByClassname = new HashMap<>();
diff --git a/sonar-java-plugin/src/test/java/org/sonar/plugins/java/JavaSensorTest.java b/sonar-java-plugin/src/test/java/org/sonar/plugins/java/JavaSensorTest.java
index 5e737422652..7ecae776712 100644
--- a/sonar-java-plugin/src/test/java/org/sonar/plugins/java/JavaSensorTest.java
+++ b/sonar-java-plugin/src/test/java/org/sonar/plugins/java/JavaSensorTest.java
@@ -561,7 +561,7 @@ void custom_file_scanner_is_not_filtered_in_autoscan() throws IOException {
     DefaultJavaResourceLocator resourceLocator = createDefaultJavaResourceLocator(context.config(), fs);
 
     CustomFileScannerHook hook = new CustomFileScannerHook();
-    CheckRegistrar[] checkRegistrars = new CheckRegistrar[] {new CustomRegistrar(), hook};
+    CheckRegistrar[] checkRegistrars = {new CustomRegistrar(), hook};
 
     ActiveRulesBuilder activeRulesBuilder = new ActiveRulesBuilder();
     GeneratedCheckList.getChecks().stream()
@@ -620,7 +620,7 @@ private SensorContextTester analyzeTwoFilesWithIssues(MapSettings settings) thro
     ClasspathForMain javaClasspath = new ClasspathForMain(context.config(), fs);
     DefaultJavaResourceLocator resourceLocator = createDefaultJavaResourceLocator(context.config(), fs);
 
-    CheckRegistrar[] checkRegistrars = new CheckRegistrar[] {new CustomRegistrar()};
+    CheckRegistrar[] checkRegistrars = {new CustomRegistrar()};
 
     ActiveRulesBuilder activeRulesBuilder = new ActiveRulesBuilder();