diff --git a/src/main/java/com/typesafe/config/ConfigConfig.java b/src/main/java/com/typesafe/config/ConfigConfig.java
index cff7119f..c915ec63 100644
--- a/src/main/java/com/typesafe/config/ConfigConfig.java
+++ b/src/main/java/com/typesafe/config/ConfigConfig.java
@@ -5,7 +5,7 @@ package com.typesafe.config;
  */
 public final class ConfigConfig {
 
-    private String rootPath;
+    final private String rootPath;
 
     /**
      * Creates a new configuration configuration.
diff --git a/src/main/java/com/typesafe/config/impl/AbstractConfigObject.java b/src/main/java/com/typesafe/config/impl/AbstractConfigObject.java
index b789b634..38b7a75d 100644
--- a/src/main/java/com/typesafe/config/impl/AbstractConfigObject.java
+++ b/src/main/java/com/typesafe/config/impl/AbstractConfigObject.java
@@ -17,7 +17,7 @@ import com.typesafe.config.ConfigValueType;
 
 abstract class AbstractConfigObject extends AbstractConfigValue implements
         ConfigObject {
-    protected ConfigTransformer transformer;
+    final protected ConfigTransformer transformer;
 
     protected AbstractConfigObject(ConfigOrigin origin,
             ConfigTransformer transformer) {
diff --git a/src/main/java/com/typesafe/config/impl/ConfigBoolean.java b/src/main/java/com/typesafe/config/impl/ConfigBoolean.java
index acbd301a..614a12e6 100644
--- a/src/main/java/com/typesafe/config/impl/ConfigBoolean.java
+++ b/src/main/java/com/typesafe/config/impl/ConfigBoolean.java
@@ -5,7 +5,7 @@ import com.typesafe.config.ConfigValueType;
 
 final class ConfigBoolean extends AbstractConfigValue {
 
-    private boolean value;
+    final private boolean value;
 
     ConfigBoolean(ConfigOrigin origin, boolean value) {
         super(origin);
diff --git a/src/main/java/com/typesafe/config/impl/ConfigDouble.java b/src/main/java/com/typesafe/config/impl/ConfigDouble.java
index c92455de..105811f6 100644
--- a/src/main/java/com/typesafe/config/impl/ConfigDouble.java
+++ b/src/main/java/com/typesafe/config/impl/ConfigDouble.java
@@ -5,7 +5,7 @@ import com.typesafe.config.ConfigValueType;
 
 final class ConfigDouble extends AbstractConfigValue {
 
-    private double value;
+    final private double value;
 
     ConfigDouble(ConfigOrigin origin, double value) {
         super(origin);
diff --git a/src/main/java/com/typesafe/config/impl/ConfigInt.java b/src/main/java/com/typesafe/config/impl/ConfigInt.java
index fb9906a6..63699363 100644
--- a/src/main/java/com/typesafe/config/impl/ConfigInt.java
+++ b/src/main/java/com/typesafe/config/impl/ConfigInt.java
@@ -5,7 +5,7 @@ import com.typesafe.config.ConfigValueType;
 
 final class ConfigInt extends AbstractConfigValue {
 
-    private int value;
+    final private int value;
 
     ConfigInt(ConfigOrigin origin, int value) {
         super(origin);
diff --git a/src/main/java/com/typesafe/config/impl/ConfigLong.java b/src/main/java/com/typesafe/config/impl/ConfigLong.java
index 274e4f6e..593b9b60 100644
--- a/src/main/java/com/typesafe/config/impl/ConfigLong.java
+++ b/src/main/java/com/typesafe/config/impl/ConfigLong.java
@@ -5,7 +5,7 @@ import com.typesafe.config.ConfigValueType;
 
 final class ConfigLong extends AbstractConfigValue {
 
-    private long value;
+    final private long value;
 
     ConfigLong(ConfigOrigin origin, long value) {
         super(origin);
diff --git a/src/main/java/com/typesafe/config/impl/ConfigString.java b/src/main/java/com/typesafe/config/impl/ConfigString.java
index 04deeda3..522d5bf5 100644
--- a/src/main/java/com/typesafe/config/impl/ConfigString.java
+++ b/src/main/java/com/typesafe/config/impl/ConfigString.java
@@ -5,7 +5,7 @@ import com.typesafe.config.ConfigValueType;
 
 final class ConfigString extends AbstractConfigValue {
 
-    private String value;
+    final private String value;
 
     ConfigString(ConfigOrigin origin, String value) {
         super(origin);
diff --git a/src/main/java/com/typesafe/config/impl/ConfigSubstitution.java b/src/main/java/com/typesafe/config/impl/ConfigSubstitution.java
index 1166a230..d55d185f 100644
--- a/src/main/java/com/typesafe/config/impl/ConfigSubstitution.java
+++ b/src/main/java/com/typesafe/config/impl/ConfigSubstitution.java
@@ -17,7 +17,7 @@ final class ConfigSubstitution extends AbstractConfigValue {
     // this is a list of String and Path where the Path
     // have to be resolved to values, then if there's more
     // than one piece everything is stringified and concatenated
-    private List<Object> pieces;
+    final private List<Object> pieces;
 
     ConfigSubstitution(ConfigOrigin origin, List<Object> pieces) {
         super(origin);
diff --git a/src/main/java/com/typesafe/config/impl/Parser.java b/src/main/java/com/typesafe/config/impl/Parser.java
index 9f2c8d85..9da6440c 100644
--- a/src/main/java/com/typesafe/config/impl/Parser.java
+++ b/src/main/java/com/typesafe/config/impl/Parser.java
@@ -106,11 +106,11 @@ final class Parser {
 
     static private final class ParseContext {
         private int lineNumber;
-        private Stack<Token> buffer;
-        private Iterator<Token> tokens;
-        private IncludeHandler includer;
-        private SyntaxFlavor flavor;
-        private ConfigOrigin baseOrigin;
+        final private Stack<Token> buffer;
+        final private Iterator<Token> tokens;
+        final private IncludeHandler includer;
+        final private SyntaxFlavor flavor;
+        final private ConfigOrigin baseOrigin;
 
         ParseContext(SyntaxFlavor flavor, ConfigOrigin origin,
                 Iterator<Token> tokens, IncludeHandler includer) {
diff --git a/src/main/java/com/typesafe/config/impl/Path.java b/src/main/java/com/typesafe/config/impl/Path.java
index 9f571fe1..7c67fc45 100644
--- a/src/main/java/com/typesafe/config/impl/Path.java
+++ b/src/main/java/com/typesafe/config/impl/Path.java
@@ -4,8 +4,8 @@ import com.typesafe.config.ConfigException;
 
 final class Path {
 
-    private String first;
-    private Path remainder;
+    final private String first;
+    final private Path remainder;
 
     Path(String first, Path remainder) {
         this.first = first;
diff --git a/src/main/java/com/typesafe/config/impl/PathBuilder.java b/src/main/java/com/typesafe/config/impl/PathBuilder.java
index 0f6a3d53..550af117 100644
--- a/src/main/java/com/typesafe/config/impl/PathBuilder.java
+++ b/src/main/java/com/typesafe/config/impl/PathBuilder.java
@@ -6,7 +6,7 @@ import com.typesafe.config.ConfigException;
 
 final class PathBuilder {
     // the keys are kept "backward" (top of stack is end of path)
-    private Stack<String> keys;
+    final private Stack<String> keys;
     private Path result;
 
     PathBuilder() {
diff --git a/src/main/java/com/typesafe/config/impl/SimpleConfigList.java b/src/main/java/com/typesafe/config/impl/SimpleConfigList.java
index 70940f21..00f331af 100644
--- a/src/main/java/com/typesafe/config/impl/SimpleConfigList.java
+++ b/src/main/java/com/typesafe/config/impl/SimpleConfigList.java
@@ -14,7 +14,7 @@ import com.typesafe.config.ConfigValueType;
 
 final class SimpleConfigList extends AbstractConfigValue implements ConfigList {
 
-    private List<AbstractConfigValue> value;
+    final private List<AbstractConfigValue> value;
 
     SimpleConfigList(ConfigOrigin origin, List<AbstractConfigValue> value) {
         super(origin);
diff --git a/src/main/java/com/typesafe/config/impl/SimpleConfigObject.java b/src/main/java/com/typesafe/config/impl/SimpleConfigObject.java
index 4ebea7de..1cca3a6d 100644
--- a/src/main/java/com/typesafe/config/impl/SimpleConfigObject.java
+++ b/src/main/java/com/typesafe/config/impl/SimpleConfigObject.java
@@ -18,7 +18,7 @@ import com.typesafe.config.ConfigValue;
 class SimpleConfigObject extends AbstractConfigObject {
 
     // this map should never be modified - assume immutable
-    private Map<String, AbstractConfigValue> value;
+    final private Map<String, AbstractConfigValue> value;
 
     SimpleConfigObject(ConfigOrigin origin, ConfigTransformer transformer,
             Map<String, AbstractConfigValue> value) {
diff --git a/src/main/java/com/typesafe/config/impl/SimpleConfigOrigin.java b/src/main/java/com/typesafe/config/impl/SimpleConfigOrigin.java
index 5d6f5012..9dd4681f 100644
--- a/src/main/java/com/typesafe/config/impl/SimpleConfigOrigin.java
+++ b/src/main/java/com/typesafe/config/impl/SimpleConfigOrigin.java
@@ -4,7 +4,7 @@ import com.typesafe.config.ConfigOrigin;
 
 final class SimpleConfigOrigin implements ConfigOrigin {
 
-    private String description;
+    final private String description;
 
     SimpleConfigOrigin(String description) {
         this.description = description;
diff --git a/src/main/java/com/typesafe/config/impl/StackTransformer.java b/src/main/java/com/typesafe/config/impl/StackTransformer.java
index 70d88107..14e3d136 100644
--- a/src/main/java/com/typesafe/config/impl/StackTransformer.java
+++ b/src/main/java/com/typesafe/config/impl/StackTransformer.java
@@ -6,7 +6,7 @@ import com.typesafe.config.ConfigValueType;
 
 final class StackTransformer implements ConfigTransformer {
 
-    private List<ConfigTransformer> stack;
+    final private List<ConfigTransformer> stack;
 
     StackTransformer(List<ConfigTransformer> stack) {
         this.stack = stack;
diff --git a/src/main/java/com/typesafe/config/impl/SubstitutionResolver.java b/src/main/java/com/typesafe/config/impl/SubstitutionResolver.java
index 3834d98a..feb99735 100644
--- a/src/main/java/com/typesafe/config/impl/SubstitutionResolver.java
+++ b/src/main/java/com/typesafe/config/impl/SubstitutionResolver.java
@@ -9,8 +9,8 @@ import java.util.Map;
  * of values or whole trees of values as we follow chains of substitutions.
  */
 final class SubstitutionResolver {
-    private AbstractConfigObject root;
-    private Map<AbstractConfigValue, AbstractConfigValue> memos;
+    final private AbstractConfigObject root;
+    final private Map<AbstractConfigValue, AbstractConfigValue> memos;
 
     SubstitutionResolver(AbstractConfigObject root) {
         this.root = root;
diff --git a/src/main/java/com/typesafe/config/impl/Token.java b/src/main/java/com/typesafe/config/impl/Token.java
index ee64ac78..1c863c87 100644
--- a/src/main/java/com/typesafe/config/impl/Token.java
+++ b/src/main/java/com/typesafe/config/impl/Token.java
@@ -1,7 +1,7 @@
 package com.typesafe.config.impl;
 
 class Token {
-    private TokenType tokenType;
+    final private TokenType tokenType;
 
     Token(TokenType tokenType) {
         this.tokenType = tokenType;
diff --git a/src/main/java/com/typesafe/config/impl/Tokenizer.java b/src/main/java/com/typesafe/config/impl/Tokenizer.java
index ccec485f..db7b0131 100644
--- a/src/main/java/com/typesafe/config/impl/Tokenizer.java
+++ b/src/main/java/com/typesafe/config/impl/Tokenizer.java
@@ -81,12 +81,12 @@ final class Tokenizer {
             }
         }
 
-        private ConfigOrigin origin;
-        private Reader input;
+        final private ConfigOrigin origin;
+        final private Reader input;
         private int oneCharBuffer;
         private int lineNumber;
-        private Queue<Token> tokens;
-        private WhitespaceSaver whitespaceSaver;
+        final private Queue<Token> tokens;
+        final private WhitespaceSaver whitespaceSaver;
 
         TokenIterator(ConfigOrigin origin, Reader input) {
             this.origin = origin;
diff --git a/src/main/java/com/typesafe/config/impl/Tokens.java b/src/main/java/com/typesafe/config/impl/Tokens.java
index 06bb0008..062b7f44 100644
--- a/src/main/java/com/typesafe/config/impl/Tokens.java
+++ b/src/main/java/com/typesafe/config/impl/Tokens.java
@@ -9,7 +9,7 @@ import com.typesafe.config.ConfigValueType;
 final class Tokens {
     static private class Value extends Token {
 
-        private AbstractConfigValue value;
+        final private AbstractConfigValue value;
 
         Value(AbstractConfigValue value) {
             super(TokenType.VALUE);
@@ -45,7 +45,7 @@ final class Tokens {
     }
 
     static private class Line extends Token {
-        private int lineNumber;
+        final private int lineNumber;
 
         Line(int lineNumber) {
             super(TokenType.NEWLINE);
@@ -80,8 +80,8 @@ final class Tokens {
 
     // This is not a Value, because it requires special processing
     static private class UnquotedText extends Token {
-        private ConfigOrigin origin;
-        private String value;
+        final private ConfigOrigin origin;
+        final private String value;
 
         UnquotedText(ConfigOrigin origin, String s) {
             super(TokenType.UNQUOTED_TEXT);
@@ -121,8 +121,8 @@ final class Tokens {
 
     // This is not a Value, because it requires special processing
     static private class Substitution extends Token {
-        private ConfigOrigin origin;
-        private List<Token> value;
+        final private ConfigOrigin origin;
+        final private List<Token> value;
 
         Substitution(ConfigOrigin origin, List<Token> expression) {
             super(TokenType.SUBSTITUTION);
@@ -234,14 +234,14 @@ final class Tokens {
         }
     }
 
-    static Token START = new Token(TokenType.START);
-    static Token END = new Token(TokenType.END);
-    static Token COMMA = new Token(TokenType.COMMA);
-    static Token COLON = new Token(TokenType.COLON);
-    static Token OPEN_CURLY = new Token(TokenType.OPEN_CURLY);
-    static Token CLOSE_CURLY = new Token(TokenType.CLOSE_CURLY);
-    static Token OPEN_SQUARE = new Token(TokenType.OPEN_SQUARE);
-    static Token CLOSE_SQUARE = new Token(TokenType.CLOSE_SQUARE);
+    final static Token START = new Token(TokenType.START);
+    final static Token END = new Token(TokenType.END);
+    final static Token COMMA = new Token(TokenType.COMMA);
+    final static Token COLON = new Token(TokenType.COLON);
+    final static Token OPEN_CURLY = new Token(TokenType.OPEN_CURLY);
+    final static Token CLOSE_CURLY = new Token(TokenType.CLOSE_CURLY);
+    final static Token OPEN_SQUARE = new Token(TokenType.OPEN_SQUARE);
+    final static Token CLOSE_SQUARE = new Token(TokenType.CLOSE_SQUARE);
 
     static Token newLine(int lineNumberJustEnded) {
         return new Line(lineNumberJustEnded);
diff --git a/src/main/java/com/typesafe/config/impl/TransformedConfigObject.java b/src/main/java/com/typesafe/config/impl/TransformedConfigObject.java
index d989f7cd..fd35cc49 100644
--- a/src/main/java/com/typesafe/config/impl/TransformedConfigObject.java
+++ b/src/main/java/com/typesafe/config/impl/TransformedConfigObject.java
@@ -8,7 +8,7 @@ import com.typesafe.config.ConfigValue;
 
 class TransformedConfigObject extends AbstractConfigObject {
 
-    private AbstractConfigObject underlying;
+    final private AbstractConfigObject underlying;
 
     TransformedConfigObject(ConfigTransformer transformer,
             AbstractConfigObject underlying) {