diff --git a/user/test/com/google/gwt/emultest/java/util/TreeMapTest.java b/user/test/com/google/gwt/emultest/java/util/TreeMapTest.java
index bef7fac..69843a2 100644
--- a/user/test/com/google/gwt/emultest/java/util/TreeMapTest.java
+++ b/user/test/com/google/gwt/emultest/java/util/TreeMapTest.java
@@ -2306,7 +2306,7 @@
   public void testPut_ComparableKey() {
     final boolean java6CompatibleSources =
         !TestUtils.isJvm() || TestUtils.getJdkVersion() < 7;
-    TreeMap<String, Object> map = new TreeMap<String, Object>();
+    TreeMap map = new TreeMap();
     ConflictingKey conflictingKey = new ConflictingKey("conflictingKey");
     try {
       TreeMap untypedMap = map;
@@ -3501,7 +3501,7 @@
   protected void verifyMap() {
     if (!TestUtils.isJvm()) {
       // Verify red-black correctness in our implementation
-      TreeMapViolator.callAssertCorrectness(map);
+      TreeMapViolator.callAssertCorrectness((TreeMap) map);
     }
     super.verifyMap();
   }
diff --git a/user/test/com/google/gwt/emultest/java/util/TreeMapViolator.java b/user/test/com/google/gwt/emultest/java/util/TreeMapViolator.java
index d2de931..80da65d 100644
--- a/user/test/com/google/gwt/emultest/java/util/TreeMapViolator.java
+++ b/user/test/com/google/gwt/emultest/java/util/TreeMapViolator.java
@@ -15,7 +15,7 @@
  */
 package com.google.gwt.emultest.java.util;
 
-import java.util.Map;
+import java.util.TreeMap;
 
 /**
  * Used to delay referencing methods only present in the emulated JRE until they
@@ -24,7 +24,7 @@
 public class TreeMapViolator {
   // Use JSNI to call a special method on our implementation of TreeMap.
   @SuppressWarnings("unchecked") // raw Map
-  public static native void callAssertCorrectness(Map map) /*-{
+  public static native void callAssertCorrectness(TreeMap map) /*-{
     map.@java.util.TreeMap::assertCorrectness()();
   }-*/;
 }