diff --git a/Mage/src/main/java/mage/util/CardUtil.java b/Mage/src/main/java/mage/util/CardUtil.java
index a007722f8fd..d40647ebae2 100644
--- a/Mage/src/main/java/mage/util/CardUtil.java
+++ b/Mage/src/main/java/mage/util/CardUtil.java
@@ -69,7 +69,7 @@ public class CardUtil {
 
     private static final String SOURCE_EXILE_ZONE_TEXT = "SourceExileZone";
 
-    static String numberStrings[] = {"zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine",
+    static final String[] numberStrings = {"zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine",
         "ten", "eleven", "twelve", "thirteen", "fourteen", "fifteen", "sixteen", "seventeen", "eighteen", "ninteen", "twenty"};
 
     public static final String[] NON_CHANGELING_SUBTYPES_VALUES = new String[]{
diff --git a/Mage/src/main/java/mage/util/CircularList.java b/Mage/src/main/java/mage/util/CircularList.java
index 27eaf144bfa..7a131d4d441 100644
--- a/Mage/src/main/java/mage/util/CircularList.java
+++ b/Mage/src/main/java/mage/util/CircularList.java
@@ -45,7 +45,7 @@ import java.util.concurrent.locks.ReentrantLock;
 public class CircularList<E> implements List<E>, Iterable<E>, Serializable {
     //TODO: might have to make E extend Copyable
 
-    protected List<E> list = new ArrayList<>();
+    protected final List<E> list = new ArrayList<>();
 
     protected final ReentrantLock lock = new ReentrantLock();
 
@@ -357,8 +357,8 @@ public class CircularList<E> implements List<E>, Iterable<E>, Serializable {
     private class CircularIterator<E> implements Iterator<E> {
 
         int cursor;
-        int lastIndex;
-        int curModCount;
+        final int lastIndex;
+        final int curModCount;
         boolean hasMoved = false;
 
         private CircularIterator() {
@@ -399,9 +399,9 @@ public class CircularList<E> implements List<E>, Iterable<E>, Serializable {
     private class CircularListIterator<E> implements ListIterator<E> {
 
         int cursor;
-        int lastIndex;
-        int firstIndex;
-        int curModCount;
+        final int lastIndex;
+        final int firstIndex;
+        final int curModCount;
         boolean hasMoved = false;
 
         private CircularListIterator() {
diff --git a/Mage/src/main/java/mage/util/CopierObjectInputStream.java b/Mage/src/main/java/mage/util/CopierObjectInputStream.java
index 72189f7b76a..cfde5cd1c17 100644
--- a/Mage/src/main/java/mage/util/CopierObjectInputStream.java
+++ b/Mage/src/main/java/mage/util/CopierObjectInputStream.java
@@ -32,7 +32,6 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.io.ObjectInputStream;
 import java.io.ObjectStreamClass;
-import java.io.StreamCorruptedException;
 
 /**
  *
diff --git a/Mage/src/main/java/mage/util/TargetAddress.java b/Mage/src/main/java/mage/util/TargetAddress.java
index 80c5724676d..0a0d1820575 100644
--- a/Mage/src/main/java/mage/util/TargetAddress.java
+++ b/Mage/src/main/java/mage/util/TargetAddress.java
@@ -42,9 +42,9 @@ import mage.target.Target;
  */
 public class TargetAddress {
 
-    protected int spellAbilityIndex;
-    protected UUID mode;
-    protected int targetIndex;
+    protected final int spellAbilityIndex;
+    protected final UUID mode;
+    protected final int targetIndex;
 
     public TargetAddress(int spellAbilityIndex, UUID mode, int targetIndex) {
         this.spellAbilityIndex = spellAbilityIndex;
@@ -68,7 +68,7 @@ public class TargetAddress {
 
     protected static class TargetAddressIterator implements Iterator<TargetAddress> {
 
-        protected Iterator<SpellAbility> spellAbilityIterator;
+        protected final Iterator<SpellAbility> spellAbilityIterator;
         protected Integer lastSpellAbilityIndex = null;
         protected Iterator<UUID> modeIterator = null;
         protected Modes modes = null;
diff --git a/Mage/src/main/java/mage/util/ThreadLocalStringBuilder.java b/Mage/src/main/java/mage/util/ThreadLocalStringBuilder.java
index bfa102d83f7..e27257936f8 100644
--- a/Mage/src/main/java/mage/util/ThreadLocalStringBuilder.java
+++ b/Mage/src/main/java/mage/util/ThreadLocalStringBuilder.java
@@ -6,7 +6,7 @@ package mage.util;
  */
 public class ThreadLocalStringBuilder extends ThreadLocal<StringBuilder> {
 
-    private int size;
+    private final int size;
     
     public ThreadLocalStringBuilder(int size) {
         this.size = size;