diff --git a/core/java/com/android/internal/util/MessageUtils.java b/core/java/com/android/internal/util/MessageUtils.java
index 1014bfd6955d1..184245ef538dc 100644
--- a/core/java/com/android/internal/util/MessageUtils.java
+++ b/core/java/com/android/internal/util/MessageUtils.java
@@ -21,6 +21,7 @@ import android.util.Log;
 import android.util.SparseArray;
 
 import java.lang.reflect.Field;
+import java.lang.reflect.Modifier;
 
 /**
  * Static utility class for dealing with {@link Message} objects.
@@ -62,8 +63,12 @@ public class MessageUtils {
             }
 
             for (Field field : fields) {
-                String name = field.getName();
+                int modifiers = field.getModifiers();
+                if (!Modifier.isStatic(modifiers) | !Modifier.isFinal(modifiers)) {
+                    continue;
+                }
 
+                String name = field.getName();
                 for (String prefix : prefixes) {
                     // Does this look like a constant?
                     if (!name.startsWith(prefix)) {
diff --git a/core/tests/utiltests/src/com/android/internal/util/MessageUtilsTest.java b/core/tests/utiltests/src/com/android/internal/util/MessageUtilsTest.java
new file mode 100644
index 0000000000000..32b969a8d1b51
--- /dev/null
+++ b/core/tests/utiltests/src/com/android/internal/util/MessageUtilsTest.java
@@ -0,0 +1,97 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.internal.util;
+
+import static org.junit.Assert.*;
+
+import com.android.internal.util.MessageUtils;
+import android.test.suitebuilder.annotation.SmallTest;
+import android.util.SparseArray;
+
+import org.junit.Test;
+
+
+class A {
+    // Should not see these.
+    private int mMember;
+    public final int CMD_NOT_STATIC = 7;
+    private static final String CMD_NOT_INT = "not an integer";
+    public static int CMD_NOT_FINAL = 34;
+    public static final int kWrongPrefix = 99;
+
+    // Should see these.
+    private static final int CMD_DO_SOMETHING = 12;
+    public static final int EVENT_SOMETHING_HAPPENED = 45;
+}
+
+class B {
+    public static final int CMD_FOO = 56;
+    public static final int EVENT_BAR = 55;
+    public static final int NOTIFICATION_BAZ = 12;
+}
+
+/**
+ * Unit tests for {@link com.android.util.MessageUtils}.
+ */
+@SmallTest
+public class MessageUtilsTest {
+
+    private static final Class[] CLASSES = { A.class, B.class };
+
+    private SparseArray<String> makeSparseArray(int[] keys, String[] values) throws Exception {
+        assertEquals("Must specify same number of keys and values", keys.length, values.length);
+        SparseArray<String> out = new SparseArray<>();
+        for (int i = 0; i < keys.length; i++) {
+            out.put(keys[i], values[i]);
+        }
+        return out;
+    }
+
+    private void assertSparseArrayEquals(
+            SparseArray<String> a1, SparseArray<String> a2) throws Exception {
+        String msg = String.format("%s != %s", a1.toString(), a2.toString());
+        assertEquals(msg, a1.size(), a2.size());
+        int size = a1.size();
+        for (int i = 0; i < size; i++) {
+            assertEquals(msg, a1.keyAt(i), a2.keyAt(i));
+            assertEquals(msg, a1.valueAt(i), a2.valueAt(i));
+        }
+    }
+
+    @Test
+    public void basicOperation() throws Exception {
+        SparseArray<String> expected = makeSparseArray(
+            new int[]{12, 45, 55, 56},
+            new String[]{"CMD_DO_SOMETHING", "EVENT_SOMETHING_HAPPENED", "EVENT_BAR", "CMD_FOO"});
+        assertSparseArrayEquals(expected, MessageUtils.findMessageNames(CLASSES));
+    }
+
+    @Test
+    public void withPrefixes() throws Exception {
+        SparseArray<String> expected = makeSparseArray(
+            new int[]{45, 55},
+            new String[]{"EVENT_SOMETHING_HAPPENED", "EVENT_BAR"});
+        assertSparseArrayEquals(expected, MessageUtils.findMessageNames(CLASSES,
+                new String[]{"EVENT_"}));
+    }
+
+    @Test(expected=MessageUtils.DuplicateConstantError.class)
+    public void duplicateConstants() {
+        MessageUtils.findMessageNames(CLASSES, new String[]{"CMD_", "NOTIFICATION_"});
+    }
+
+}