diff --git a/src/org/jetbrains/java/decompiler/code/interpreter/InstructionImpact.java b/src/org/jetbrains/java/decompiler/code/interpreter/InstructionImpact.java
index 5c56593..aeafe5c 100644
--- a/src/org/jetbrains/java/decompiler/code/interpreter/InstructionImpact.java
+++ b/src/org/jetbrains/java/decompiler/code/interpreter/InstructionImpact.java
@@ -1,4 +1,4 @@
-// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package org.jetbrains.java.decompiler.code.interpreter;
 
 import org.jetbrains.java.decompiler.code.CodeConstants;
@@ -12,7 +12,7 @@ import org.jetbrains.java.decompiler.struct.gen.MethodDescriptor;
 import org.jetbrains.java.decompiler.struct.gen.VarType;
 import org.jetbrains.java.decompiler.util.ListStack;
 
-public class InstructionImpact {
+public final class InstructionImpact {
 
   // {read, write}
   private static final int[][][] stack_impact = {
diff --git a/src/org/jetbrains/java/decompiler/main/AssertProcessor.java b/src/org/jetbrains/java/decompiler/main/AssertProcessor.java
index b0e7b71..a8863c5 100644
--- a/src/org/jetbrains/java/decompiler/main/AssertProcessor.java
+++ b/src/org/jetbrains/java/decompiler/main/AssertProcessor.java
@@ -1,4 +1,4 @@
-// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package org.jetbrains.java.decompiler.main;
 
 import org.jetbrains.java.decompiler.code.CodeConstants;
@@ -21,7 +21,7 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 
-public class AssertProcessor {
+public final class AssertProcessor {
 
   private static final VarType CLASS_ASSERTION_ERROR = new VarType(CodeConstants.TYPE_OBJECT, 0, "java/lang/AssertionError");
 
diff --git a/src/org/jetbrains/java/decompiler/main/ClassReference14Processor.java b/src/org/jetbrains/java/decompiler/main/ClassReference14Processor.java
index 41b5a9a..e082267 100644
--- a/src/org/jetbrains/java/decompiler/main/ClassReference14Processor.java
+++ b/src/org/jetbrains/java/decompiler/main/ClassReference14Processor.java
@@ -1,4 +1,4 @@
-// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package org.jetbrains.java.decompiler.main;
 
 import org.jetbrains.java.decompiler.code.CodeConstants;
@@ -22,7 +22,7 @@ import org.jetbrains.java.decompiler.util.VBStyleCollection;
 import java.util.*;
 import java.util.Map.Entry;
 
-public class ClassReference14Processor {
+public final class ClassReference14Processor {
   private static final ExitExprent BODY_EXPR;
   private static final ExitExprent HANDLER_EXPR;
 
diff --git a/src/org/jetbrains/java/decompiler/main/EnumProcessor.java b/src/org/jetbrains/java/decompiler/main/EnumProcessor.java
index 08598e8..7f6beef 100644
--- a/src/org/jetbrains/java/decompiler/main/EnumProcessor.java
+++ b/src/org/jetbrains/java/decompiler/main/EnumProcessor.java
@@ -1,4 +1,4 @@
-// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package org.jetbrains.java.decompiler.main;
 
 import org.jetbrains.java.decompiler.code.CodeConstants;
@@ -13,7 +13,7 @@ import org.jetbrains.java.decompiler.struct.StructField;
 import org.jetbrains.java.decompiler.struct.StructMethod;
 import org.jetbrains.java.decompiler.util.InterpreterUtil;
 
-public class EnumProcessor {
+public final class EnumProcessor {
   public static void clearEnum(ClassWrapper wrapper) {
     StructClass cl = wrapper.getClassStruct();
 
diff --git a/src/org/jetbrains/java/decompiler/main/InitializerProcessor.java b/src/org/jetbrains/java/decompiler/main/InitializerProcessor.java
index b929d0d..d3696dd 100644
--- a/src/org/jetbrains/java/decompiler/main/InitializerProcessor.java
+++ b/src/org/jetbrains/java/decompiler/main/InitializerProcessor.java
@@ -1,4 +1,4 @@
-// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package org.jetbrains.java.decompiler.main;
 
 import org.jetbrains.java.decompiler.code.CodeConstants;
@@ -18,7 +18,7 @@ import org.jetbrains.java.decompiler.util.InterpreterUtil;
 import java.util.ArrayList;
 import java.util.List;
 
-public class InitializerProcessor {
+public final class InitializerProcessor {
   public static void extractInitializers(ClassWrapper wrapper) {
     MethodWrapper method = wrapper.getMethodWrapper(CodeConstants.CLINIT_NAME, "()V");
     if (method != null && method.root != null) {  // successfully decompiled static constructor
diff --git a/src/org/jetbrains/java/decompiler/modules/code/DeadCodeHelper.java b/src/org/jetbrains/java/decompiler/modules/code/DeadCodeHelper.java
index 9d28d0e..421ed98 100644
--- a/src/org/jetbrains/java/decompiler/modules/code/DeadCodeHelper.java
+++ b/src/org/jetbrains/java/decompiler/modules/code/DeadCodeHelper.java
@@ -1,4 +1,4 @@
-// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package org.jetbrains.java.decompiler.modules.code;
 
 import org.jetbrains.java.decompiler.code.CodeConstants;
@@ -13,7 +13,7 @@ import org.jetbrains.java.decompiler.main.extern.IFernflowerPreferences;
 
 import java.util.*;
 
-public class DeadCodeHelper {
+public final class DeadCodeHelper {
 
   public static void removeDeadBlocks(ControlFlowGraph graph) {
 
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/ClasspathHelper.java b/src/org/jetbrains/java/decompiler/modules/decompiler/ClasspathHelper.java
index 6e1155d..d6a7ed8 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/ClasspathHelper.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/ClasspathHelper.java
@@ -1,4 +1,4 @@
-// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package org.jetbrains.java.decompiler.modules.decompiler;
 
 import org.jetbrains.java.decompiler.struct.gen.MethodDescriptor;
@@ -9,7 +9,7 @@ import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
 
-public class ClasspathHelper {
+public final class ClasspathHelper {
 
   private static final Map<String, Method> METHOD_CACHE = Collections.synchronizedMap(new HashMap<>());
 
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/ClearStructHelper.java b/src/org/jetbrains/java/decompiler/modules/decompiler/ClearStructHelper.java
index ede1dda..14576cc 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/ClearStructHelper.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/ClearStructHelper.java
@@ -1,4 +1,4 @@
-// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package org.jetbrains.java.decompiler.modules.decompiler;
 
 import org.jetbrains.java.decompiler.modules.decompiler.stats.RootStatement;
@@ -7,7 +7,7 @@ import org.jetbrains.java.decompiler.modules.decompiler.stats.Statement;
 import java.util.LinkedList;
 
 
-public class ClearStructHelper {
+public final class ClearStructHelper {
 
   public static void clearStatements(RootStatement root) {
 
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/ConcatenationHelper.java b/src/org/jetbrains/java/decompiler/modules/decompiler/ConcatenationHelper.java
index 7d5c207..3b255be 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/ConcatenationHelper.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/ConcatenationHelper.java
@@ -1,4 +1,4 @@
-// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package org.jetbrains.java.decompiler.modules.decompiler;
 
 import org.jetbrains.java.decompiler.code.CodeConstants;
@@ -13,7 +13,7 @@ import java.util.Arrays;
 import java.util.List;
 import java.util.Set;
 
-public class ConcatenationHelper {
+public final class ConcatenationHelper {
 
   private static final String builderClass = "java/lang/StringBuilder";
   private static final String bufferClass = "java/lang/StringBuffer";
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/DecHelper.java b/src/org/jetbrains/java/decompiler/modules/decompiler/DecHelper.java
index 1549734..50613fc 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/DecHelper.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/DecHelper.java
@@ -1,4 +1,4 @@
-// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package org.jetbrains.java.decompiler.modules.decompiler;
 
 import org.jetbrains.java.decompiler.modules.decompiler.exps.Exprent;
@@ -10,7 +10,7 @@ import java.util.List;
 import java.util.Set;
 
 
-public class DecHelper {
+public final class DecHelper {
 
   public static boolean checkStatementExceptions(List<? extends Statement> lst) {
 
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/DomHelper.java b/src/org/jetbrains/java/decompiler/modules/decompiler/DomHelper.java
index 2c5e3eb..7ef6d2f 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/DomHelper.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/DomHelper.java
@@ -1,4 +1,4 @@
-// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package org.jetbrains.java.decompiler.modules.decompiler;
 
 import org.jetbrains.java.decompiler.code.cfg.BasicBlock;
@@ -16,7 +16,7 @@ import org.jetbrains.java.decompiler.util.VBStyleCollection;
 
 import java.util.*;
 
-public class DomHelper {
+public final class DomHelper {
 
 
   private static RootStatement graphToStatement(ControlFlowGraph graph) {
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/ExitHelper.java b/src/org/jetbrains/java/decompiler/modules/decompiler/ExitHelper.java
index 3b9847f..8e0ac9c 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/ExitHelper.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/ExitHelper.java
@@ -1,4 +1,4 @@
-// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package org.jetbrains.java.decompiler.modules.decompiler;
 
 import org.jetbrains.java.decompiler.code.cfg.BasicBlock;
@@ -13,7 +13,7 @@ import java.util.Arrays;
 import java.util.List;
 import java.util.Set;
 
-public class ExitHelper {
+public final class ExitHelper {
   public static boolean condenseExits(RootStatement root) {
     int changed = integrateExits(root);
 
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/IdeaNotNullHelper.java b/src/org/jetbrains/java/decompiler/modules/decompiler/IdeaNotNullHelper.java
index 9598b3c..ff45d29 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/IdeaNotNullHelper.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/IdeaNotNullHelper.java
@@ -1,4 +1,4 @@
-// Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package org.jetbrains.java.decompiler.modules.decompiler;
 
 import org.jetbrains.java.decompiler.code.CodeConstants;
@@ -14,7 +14,7 @@ import org.jetbrains.java.decompiler.struct.gen.MethodDescriptor;
 
 import java.util.List;
 
-public class IdeaNotNullHelper {
+public final class IdeaNotNullHelper {
 
 
   public static boolean removeHardcodedChecks(Statement root, StructMethod mt) {
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/IfHelper.java b/src/org/jetbrains/java/decompiler/modules/decompiler/IfHelper.java
index 89bfae3..afcf55e 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/IfHelper.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/IfHelper.java
@@ -1,4 +1,4 @@
-// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package org.jetbrains.java.decompiler.modules.decompiler;
 
 import org.jetbrains.java.decompiler.modules.decompiler.exps.Exprent;
@@ -11,7 +11,7 @@ import org.jetbrains.java.decompiler.modules.decompiler.stats.Statement;
 
 import java.util.*;
 
-public class IfHelper {
+public final class IfHelper {
   public static boolean mergeAllIfs(RootStatement root) {
     boolean res = mergeAllIfsRec(root, new HashSet<>());
     if (res) {
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/InlineSingleBlockHelper.java b/src/org/jetbrains/java/decompiler/modules/decompiler/InlineSingleBlockHelper.java
index f6ee600..0c94761 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/InlineSingleBlockHelper.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/InlineSingleBlockHelper.java
@@ -1,4 +1,4 @@
-// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package org.jetbrains.java.decompiler.modules.decompiler;
 
 import org.jetbrains.java.decompiler.modules.decompiler.stats.*;
@@ -7,7 +7,7 @@ import java.util.ArrayList;
 import java.util.List;
 
 
-public class InlineSingleBlockHelper {
+public final class InlineSingleBlockHelper {
 
 
   public static boolean inlineSingleBlocks(RootStatement root) {
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/LabelHelper.java b/src/org/jetbrains/java/decompiler/modules/decompiler/LabelHelper.java
index 9c150b5..bf4d889 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/LabelHelper.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/LabelHelper.java
@@ -1,4 +1,4 @@
-// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package org.jetbrains.java.decompiler.modules.decompiler;
 
 import org.jetbrains.java.decompiler.modules.decompiler.exps.Exprent;
@@ -8,7 +8,7 @@ import java.util.*;
 import java.util.Map.Entry;
 
 
-public class LabelHelper {
+public final class LabelHelper {
 
 
   public static void cleanUpEdges(RootStatement root) {
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/LoopExtractHelper.java b/src/org/jetbrains/java/decompiler/modules/decompiler/LoopExtractHelper.java
index 8229127..b82562e 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/LoopExtractHelper.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/LoopExtractHelper.java
@@ -1,4 +1,4 @@
-// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package org.jetbrains.java.decompiler.modules.decompiler;
 
 import org.jetbrains.java.decompiler.modules.decompiler.stats.DoStatement;
@@ -11,7 +11,7 @@ import java.util.Arrays;
 import java.util.Set;
 
 
-public class LoopExtractHelper {
+public final class LoopExtractHelper {
 
 
   public static boolean extractLoops(Statement root) {
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/MergeHelper.java b/src/org/jetbrains/java/decompiler/modules/decompiler/MergeHelper.java
index ed9f368..77c3dc3 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/MergeHelper.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/MergeHelper.java
@@ -1,4 +1,4 @@
-// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package org.jetbrains.java.decompiler.modules.decompiler;
 
 import org.jetbrains.java.decompiler.code.cfg.BasicBlock;
@@ -12,7 +12,7 @@ import java.util.ArrayList;
 import java.util.List;
 import java.util.Set;
 
-public class MergeHelper {
+public final class MergeHelper {
   public static void enhanceLoops(Statement root) {
     while (enhanceLoopsRec(root)) /**/;
     SequenceHelper.condenseSequences(root);
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/SecondaryFunctionsHelper.java b/src/org/jetbrains/java/decompiler/modules/decompiler/SecondaryFunctionsHelper.java
index 17bf65e..beaa6c2 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/SecondaryFunctionsHelper.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/SecondaryFunctionsHelper.java
@@ -16,7 +16,7 @@ import java.util.Arrays;
 import java.util.HashMap;
 import java.util.List;
 
-public class SecondaryFunctionsHelper {
+public final class SecondaryFunctionsHelper {
 
   private static final int[] funcsnot = new int[]{
     FunctionExprent.FUNCTION_NE,
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/SequenceHelper.java b/src/org/jetbrains/java/decompiler/modules/decompiler/SequenceHelper.java
index 4fe4127..2e00b7a 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/SequenceHelper.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/SequenceHelper.java
@@ -1,4 +1,4 @@
-// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package org.jetbrains.java.decompiler.modules.decompiler;
 
 import org.jetbrains.java.decompiler.code.cfg.BasicBlock;
@@ -13,7 +13,7 @@ import java.util.HashSet;
 import java.util.List;
 
 
-public class SequenceHelper {
+public final class SequenceHelper {
 
 
   public static void condenseSequences(Statement root) {
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/SwitchHelper.java b/src/org/jetbrains/java/decompiler/modules/decompiler/SwitchHelper.java
index b49bf39..1e08a6d 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/SwitchHelper.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/SwitchHelper.java
@@ -1,4 +1,4 @@
-// Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package org.jetbrains.java.decompiler.modules.decompiler;
 
 import org.jetbrains.java.decompiler.code.CodeConstants;
@@ -14,7 +14,7 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
-public class SwitchHelper {
+public final class SwitchHelper {
   public static void simplify(SwitchStatement switchStatement) {
     SwitchExprent switchExprent = (SwitchExprent)switchStatement.getHeadexprent();
     Exprent value = switchExprent.getValue();
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/deobfuscator/ExceptionDeobfuscator.java b/src/org/jetbrains/java/decompiler/modules/decompiler/deobfuscator/ExceptionDeobfuscator.java
index cc02d0f..c0a7769 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/deobfuscator/ExceptionDeobfuscator.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/deobfuscator/ExceptionDeobfuscator.java
@@ -18,7 +18,7 @@ import org.jetbrains.java.decompiler.util.InterpreterUtil;
 import java.util.*;
 import java.util.Map.Entry;
 
-public class ExceptionDeobfuscator {
+public final class ExceptionDeobfuscator {
 
   private static final class Range {
     private final BasicBlock handler;
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/deobfuscator/IrreducibleCFGDeobfuscator.java b/src/org/jetbrains/java/decompiler/modules/decompiler/deobfuscator/IrreducibleCFGDeobfuscator.java
index 7fecbd9..9cab6a5 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/deobfuscator/IrreducibleCFGDeobfuscator.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/deobfuscator/IrreducibleCFGDeobfuscator.java
@@ -1,4 +1,4 @@
-// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package org.jetbrains.java.decompiler.modules.decompiler.deobfuscator;
 
 import org.jetbrains.java.decompiler.modules.decompiler.StatEdge;
@@ -10,7 +10,7 @@ import java.util.HashSet;
 import java.util.Set;
 
 
-public class IrreducibleCFGDeobfuscator {
+public final class IrreducibleCFGDeobfuscator {
 
 
   public static boolean isStatementIrreducible(Statement statement) {
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/exps/ExprUtil.java b/src/org/jetbrains/java/decompiler/modules/decompiler/exps/ExprUtil.java
index 302d62f..58a653a 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/exps/ExprUtil.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/exps/ExprUtil.java
@@ -1,4 +1,4 @@
-// Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package org.jetbrains.java.decompiler.modules.decompiler.exps;
 
 import org.jetbrains.java.decompiler.code.CodeConstants;
@@ -13,7 +13,7 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 
-public class ExprUtil {
+public final class ExprUtil {
   public static List<VarVersionPair> getSyntheticParametersMask(String className, String descriptor, int parameters) {
     ClassNode node = DecompilerContext.getClassProcessor().getMapRootClasses().get(className);
     return node != null ? getSyntheticParametersMask(node, descriptor, parameters) : null;
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/stats/Statements.java b/src/org/jetbrains/java/decompiler/modules/decompiler/stats/Statements.java
index cadf50f..891ba35 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/stats/Statements.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/stats/Statements.java
@@ -1,4 +1,4 @@
-// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package org.jetbrains.java.decompiler.modules.decompiler.stats;
 
 import org.jetbrains.java.decompiler.main.rels.ClassWrapper;
@@ -8,7 +8,7 @@ import org.jetbrains.java.decompiler.modules.decompiler.exps.InvocationExprent;
 import org.jetbrains.java.decompiler.modules.decompiler.exps.VarExprent;
 import org.jetbrains.java.decompiler.modules.decompiler.vars.VarVersionPair;
 
-public class Statements {
+public final class Statements {
   public static Statement findFirstData(Statement stat) {
     if (stat.getExprents() != null) {
       return stat;
diff --git a/src/org/jetbrains/java/decompiler/struct/gen/generics/GenericMain.java b/src/org/jetbrains/java/decompiler/struct/gen/generics/GenericMain.java
index 3e4e1f1..8af6b50 100644
--- a/src/org/jetbrains/java/decompiler/struct/gen/generics/GenericMain.java
+++ b/src/org/jetbrains/java/decompiler/struct/gen/generics/GenericMain.java
@@ -1,4 +1,4 @@
-// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package org.jetbrains.java.decompiler.struct.gen.generics;
 
 import org.jetbrains.java.decompiler.code.CodeConstants;
@@ -9,7 +9,7 @@ import org.jetbrains.java.decompiler.util.TextUtil;
 import java.util.ArrayList;
 import java.util.List;
 
-public class GenericMain {
+public final class GenericMain {
 
   private static final String[] typeNames = {
     "byte",
diff --git a/src/org/jetbrains/java/decompiler/util/InterpreterUtil.java b/src/org/jetbrains/java/decompiler/util/InterpreterUtil.java
index 1d29253..0ba7dc4 100644
--- a/src/org/jetbrains/java/decompiler/util/InterpreterUtil.java
+++ b/src/org/jetbrains/java/decompiler/util/InterpreterUtil.java
@@ -1,4 +1,4 @@
-// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package org.jetbrains.java.decompiler.util;
 
 import java.io.*;
@@ -8,7 +8,7 @@ import java.util.List;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipFile;
 
-public class InterpreterUtil {
+public final class InterpreterUtil {
   public static final boolean IS_WINDOWS = System.getProperty("os.name", "").startsWith("Windows");
 
   public static final int[] EMPTY_INT_ARRAY = new int[0];
diff --git a/src/org/jetbrains/java/decompiler/util/TextUtil.java b/src/org/jetbrains/java/decompiler/util/TextUtil.java
index 3d92d2e..e2a08f0 100644
--- a/src/org/jetbrains/java/decompiler/util/TextUtil.java
+++ b/src/org/jetbrains/java/decompiler/util/TextUtil.java
@@ -1,6 +1,4 @@
-/*
- * Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
- */
+// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package org.jetbrains.java.decompiler.util;
 
 import org.jetbrains.java.decompiler.code.CodeConstants;
@@ -12,7 +10,7 @@ import org.jetbrains.java.decompiler.modules.decompiler.ExprProcessor;
 import java.util.Arrays;
 import java.util.HashSet;
 
-public class TextUtil {
+public final class TextUtil {
   private static final HashSet<String> KEYWORDS = new HashSet<>(Arrays.asList(
     "abstract", "default", "if", "private", "this", "boolean", "do", "implements", "protected", "throw", "break", "double", "import",
     "public", "throws", "byte", "else", "instanceof", "return", "transient", "case", "extends", "int", "short", "try", "catch", "final",