diff --git a/src/com/google/javascript/jscomp/ChromeCodingConvention.java b/src/com/google/javascript/jscomp/ChromeCodingConvention.java
index 59c857d6bda..31b84ada1ea 100644
--- a/src/com/google/javascript/jscomp/ChromeCodingConvention.java
+++ b/src/com/google/javascript/jscomp/ChromeCodingConvention.java
@@ -17,15 +17,16 @@
 
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
+import com.google.errorprone.annotations.Immutable;
 import com.google.javascript.jscomp.ClosureCodingConvention.AssertInstanceofSpec;
 import com.google.javascript.rhino.Node;
 import com.google.javascript.rhino.jstype.FunctionType;
 import com.google.javascript.rhino.jstype.ObjectType;
 import java.util.Collection;
-import java.util.Set;
 
-public class ChromeCodingConvention extends CodingConventions.Proxy {
-  private final Set<String> indirectlyDeclaredProperties;
+@Immutable
+public final class ChromeCodingConvention extends CodingConventions.Proxy {
+  private final ImmutableSet<String> indirectlyDeclaredProperties;
 
   public ChromeCodingConvention() {
     this(CodingConventions.getDefault());
diff --git a/src/com/google/javascript/jscomp/ClosureCodingConvention.java b/src/com/google/javascript/jscomp/ClosureCodingConvention.java
index d3e0417ae80..b4b0285f585 100644
--- a/src/com/google/javascript/jscomp/ClosureCodingConvention.java
+++ b/src/com/google/javascript/jscomp/ClosureCodingConvention.java
@@ -19,6 +19,7 @@
 import com.google.common.base.Preconditions;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
+import com.google.errorprone.annotations.Immutable;
 import com.google.javascript.jscomp.newtypes.DeclaredTypeRegistry;
 import com.google.javascript.jscomp.newtypes.JSType;
 import com.google.javascript.jscomp.newtypes.QualifiedName;
@@ -32,12 +33,12 @@
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
-import java.util.Set;
 
 /**
  * This describes the Closure-specific JavaScript coding conventions.
  *
  */
+@Immutable
 public final class ClosureCodingConvention extends CodingConventions.Proxy {
 
   private static final long serialVersionUID = 1L;
@@ -46,7 +47,7 @@ public final class ClosureCodingConvention extends CodingConventions.Proxy {
       "JSC_REFLECT_OBJECTLIT_EXPECTED",
       "Object literal expected as second argument");
 
-  private final Set<String> indirectlyDeclaredProperties;
+  private final ImmutableSet<String> indirectlyDeclaredProperties;
 
   public ClosureCodingConvention() {
     this(CodingConventions.getDefault());
@@ -345,7 +346,7 @@ public boolean isAliasingGlobalThis(Node n) {
     return CodingConventions.isAliasingGlobalThis(this, n);
   }
 
-  private final Set<String> propertyTestFunctions = ImmutableSet.of(
+  private final ImmutableSet<String> propertyTestFunctions = ImmutableSet.of(
       "goog.isDef", "goog.isNull", "goog.isDefAndNotNull",
       "goog.isString", "goog.isNumber", "goog.isBoolean",
       "goog.isFunction", "goog.isArray", "goog.isArrayLike", "goog.isObject");
diff --git a/src/com/google/javascript/jscomp/CodingConvention.java b/src/com/google/javascript/jscomp/CodingConvention.java
index 1ff54d5be48..fa08d172de6 100644
--- a/src/com/google/javascript/jscomp/CodingConvention.java
+++ b/src/com/google/javascript/jscomp/CodingConvention.java
@@ -15,6 +15,7 @@
  */
 package com.google.javascript.jscomp;
 
+import com.google.errorprone.annotations.Immutable;
 import com.google.javascript.jscomp.newtypes.DeclaredTypeRegistry;
 import com.google.javascript.jscomp.newtypes.JSType;
 import com.google.javascript.jscomp.newtypes.RawNominalType;
@@ -35,6 +36,7 @@
  * Compiler for a specific team/company.
  *
  */
+@Immutable
 public interface CodingConvention extends Serializable {
 
   /**
diff --git a/src/com/google/javascript/jscomp/CodingConventions.java b/src/com/google/javascript/jscomp/CodingConventions.java
index 79c86eddf30..3382322cdea 100644
--- a/src/com/google/javascript/jscomp/CodingConventions.java
+++ b/src/com/google/javascript/jscomp/CodingConventions.java
@@ -18,6 +18,7 @@
 
 import com.google.common.base.Preconditions;
 import com.google.common.collect.ImmutableList;
+import com.google.errorprone.annotations.Immutable;
 import com.google.javascript.jscomp.newtypes.JSType;
 import com.google.javascript.jscomp.newtypes.RawNominalType;
 import com.google.javascript.rhino.Node;
@@ -83,6 +84,7 @@ static boolean isAliasingGlobalThis(CodingConvention convention, Node n) {
    * coding convention by creating a jQueryCodingConvention that delegates
    * to a ClosureCodingConvention that delegates to a DefaultCodingConvention.
    */
+  @Immutable
   public static class Proxy implements CodingConvention {
 
     protected final CodingConvention nextConvention;
@@ -330,6 +332,7 @@ public Collection<String> getIndirectlyDeclaredProperties() {
    * The default coding convention.
    * Should be at the bottom of all proxy chains.
    */
+  @Immutable
   private static class DefaultCodingConvention implements CodingConvention {
 
     private static final long serialVersionUID = 1L;
diff --git a/src/com/google/javascript/jscomp/GoogleCodingConvention.java b/src/com/google/javascript/jscomp/GoogleCodingConvention.java
index b543fd9f0f9..6cb2068e911 100644
--- a/src/com/google/javascript/jscomp/GoogleCodingConvention.java
+++ b/src/com/google/javascript/jscomp/GoogleCodingConvention.java
@@ -16,6 +16,7 @@
 
 package com.google.javascript.jscomp;
 
+import com.google.errorprone.annotations.Immutable;
 import com.google.javascript.rhino.Node;
 import com.google.javascript.rhino.StaticSourceFile;
 import java.util.regex.Matcher;
@@ -26,7 +27,8 @@
  * Within Google, variable names are semantically significant.
  *
  */
-public class GoogleCodingConvention extends CodingConventions.Proxy {
+@Immutable
+public final class GoogleCodingConvention extends CodingConventions.Proxy {
 
   private static final long serialVersionUID = 1L;