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diff --git a/java/src/org/kelar/inputmethod/latin/UserBinaryDictionary.java b/java/src/org/kelar/inputmethod/latin/UserBinaryDictionary.java
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+++ b/java/src/org/kelar/inputmethod/latin/UserBinaryDictionary.java
@@ -0,0 +1,216 @@
+/*
+ * Copyright (C) 2012 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 org.kelar.inputmethod.latin;
+
+import android.content.ContentResolver;
+import android.content.Context;
+import android.database.ContentObserver;
+import android.database.Cursor;
+import android.database.sqlite.SQLiteException;
+import android.net.Uri;
+import android.provider.UserDictionary.Words;
+import android.text.TextUtils;
+import android.util.Log;
+
+import org.kelar.inputmethod.annotations.ExternallyReferenced;
+import org.kelar.inputmethod.latin.utils.SubtypeLocaleUtils;
+
+import java.io.File;
+import java.util.Arrays;
+import java.util.Locale;
+
+import javax.annotation.Nullable;
+
+/**
+ * An expandable dictionary that stores the words in the user dictionary provider into a binary
+ * dictionary file to use it from native code.
+ */
+public class UserBinaryDictionary extends ExpandableBinaryDictionary {
+    private static final String TAG = ExpandableBinaryDictionary.class.getSimpleName();
+
+    // The user dictionary provider uses an empty string to mean "all languages".
+    private static final String USER_DICTIONARY_ALL_LANGUAGES = "";
+    private static final int HISTORICAL_DEFAULT_USER_DICTIONARY_FREQUENCY = 250;
+    private static final int LATINIME_DEFAULT_USER_DICTIONARY_FREQUENCY = 160;
+
+    private static final String[] PROJECTION_QUERY = new String[] {Words.WORD, Words.FREQUENCY};
+
+    private static final String NAME = "userunigram";
+
+    private ContentObserver mObserver;
+    final private String mLocaleString;
+    final private boolean mAlsoUseMoreRestrictiveLocales;
+
+    protected UserBinaryDictionary(final Context context, final Locale locale,
+                                   final boolean alsoUseMoreRestrictiveLocales,
+                                   final File dictFile, final String name) {
+        super(context, getDictName(name, locale, dictFile), locale, Dictionary.TYPE_USER, dictFile);
+        if (null == locale) throw new NullPointerException(); // Catch the error earlier
+        final String localeStr = locale.toString();
+        if (SubtypeLocaleUtils.NO_LANGUAGE.equals(localeStr)) {
+            // If we don't have a locale, insert into the "all locales" user dictionary.
+            mLocaleString = USER_DICTIONARY_ALL_LANGUAGES;
+        } else {
+            mLocaleString = localeStr;
+        }
+        mAlsoUseMoreRestrictiveLocales = alsoUseMoreRestrictiveLocales;
+        ContentResolver cres = context.getContentResolver();
+
+        mObserver = new ContentObserver(null) {
+            @Override
+            public void onChange(final boolean self) {
+                // This hook is deprecated as of API level 16 (Build.VERSION_CODES.JELLY_BEAN),
+                // but should still be supported for cases where the IME is running on an older
+                // version of the platform.
+                onChange(self, null);
+            }
+            // The following hook is only available as of API level 16
+            // (Build.VERSION_CODES.JELLY_BEAN), and as such it will only work on JellyBean+
+            // devices. On older versions of the platform, the hook above will be called instead.
+            @Override
+            public void onChange(final boolean self, final Uri uri) {
+                setNeedsToRecreate();
+            }
+        };
+        cres.registerContentObserver(Words.CONTENT_URI, true, mObserver);
+        reloadDictionaryIfRequired();
+    }
+
+    // Note: This method is called by {@link DictionaryFacilitator} using Java reflection.
+    @ExternallyReferenced
+    public static UserBinaryDictionary getDictionary(
+            final Context context, final Locale locale, final File dictFile,
+            final String dictNamePrefix, @Nullable final String account) {
+        return new UserBinaryDictionary(
+                context, locale, false /* alsoUseMoreRestrictiveLocales */,
+                dictFile, dictNamePrefix + NAME);
+    }
+
+    @Override
+    public synchronized void close() {
+        if (mObserver != null) {
+            mContext.getContentResolver().unregisterContentObserver(mObserver);
+            mObserver = null;
+        }
+        super.close();
+    }
+
+    @Override
+    public void loadInitialContentsLocked() {
+        // Split the locale. For example "en" => ["en"], "de_DE" => ["de", "DE"],
+        // "en_US_foo_bar_qux" => ["en", "US", "foo_bar_qux"] because of the limit of 3.
+        // This is correct for locale processing.
+        // For this example, we'll look at the "en_US_POSIX" case.
+        final String[] localeElements =
+                TextUtils.isEmpty(mLocaleString) ? new String[] {} : mLocaleString.split("_", 3);
+        final int length = localeElements.length;
+
+        final StringBuilder request = new StringBuilder("(locale is NULL)");
+        String localeSoFar = "";
+        // At start, localeElements = ["en", "US", "POSIX"] ; localeSoFar = "" ;
+        // and request = "(locale is NULL)"
+        for (int i = 0; i < length; ++i) {
+            // i | localeSoFar    | localeElements
+            // 0 | ""             | ["en", "US", "POSIX"]
+            // 1 | "en_"          | ["en", "US", "POSIX"]
+            // 2 | "en_US_"       | ["en", "en_US", "POSIX"]
+            localeElements[i] = localeSoFar + localeElements[i];
+            localeSoFar = localeElements[i] + "_";
+            // i | request
+            // 0 | "(locale is NULL)"
+            // 1 | "(locale is NULL) or (locale=?)"
+            // 2 | "(locale is NULL) or (locale=?) or (locale=?)"
+            request.append(" or (locale=?)");
+        }
+        // At the end, localeElements = ["en", "en_US", "en_US_POSIX"]; localeSoFar = en_US_POSIX_"
+        // and request = "(locale is NULL) or (locale=?) or (locale=?) or (locale=?)"
+
+        final String[] requestArguments;
+        // If length == 3, we already have all the arguments we need (common prefix is meaningless
+        // inside variants
+        if (mAlsoUseMoreRestrictiveLocales && length < 3) {
+            request.append(" or (locale like ?)");
+            // The following creates an array with one more (null) position
+            final String[] localeElementsWithMoreRestrictiveLocalesIncluded =
+                    Arrays.copyOf(localeElements, length + 1);
+            localeElementsWithMoreRestrictiveLocalesIncluded[length] =
+                    localeElements[length - 1] + "_%";
+            requestArguments = localeElementsWithMoreRestrictiveLocalesIncluded;
+            // If for example localeElements = ["en"]
+            // then requestArguments = ["en", "en_%"]
+            // and request = (locale is NULL) or (locale=?) or (locale like ?)
+            // If localeElements = ["en", "en_US"]
+            // then requestArguments = ["en", "en_US", "en_US_%"]
+        } else {
+            requestArguments = localeElements;
+        }
+        final String requestString = request.toString();
+        addWordsFromProjectionLocked(PROJECTION_QUERY, requestString, requestArguments);
+    }
+
+    private void addWordsFromProjectionLocked(final String[] query, String request,
+                                              final String[] requestArguments)
+            throws IllegalArgumentException {
+        Cursor cursor = null;
+        try {
+            cursor = mContext.getContentResolver().query(
+                    Words.CONTENT_URI, query, request, requestArguments, null);
+            addWordsLocked(cursor);
+        } catch (final SQLiteException e) {
+            Log.e(TAG, "SQLiteException in the remote User dictionary process.", e);
+        } finally {
+            try {
+                if (null != cursor) cursor.close();
+            } catch (final SQLiteException e) {
+                Log.e(TAG, "SQLiteException in the remote User dictionary process.", e);
+            }
+        }
+    }
+
+    private static int scaleFrequencyFromDefaultToLatinIme(final int defaultFrequency) {
+        // The default frequency for the user dictionary is 250 for historical reasons.
+        // Latin IME considers a good value for the default user dictionary frequency
+        // is about 160 considering the scale we use. So we are scaling down the values.
+        if (defaultFrequency > Integer.MAX_VALUE / LATINIME_DEFAULT_USER_DICTIONARY_FREQUENCY) {
+            return (defaultFrequency / HISTORICAL_DEFAULT_USER_DICTIONARY_FREQUENCY)
+                    * LATINIME_DEFAULT_USER_DICTIONARY_FREQUENCY;
+        }
+        return (defaultFrequency * LATINIME_DEFAULT_USER_DICTIONARY_FREQUENCY)
+                / HISTORICAL_DEFAULT_USER_DICTIONARY_FREQUENCY;
+    }
+
+    private void addWordsLocked(final Cursor cursor) {
+        if (cursor == null) return;
+        if (cursor.moveToFirst()) {
+            final int indexWord = cursor.getColumnIndex(Words.WORD);
+            final int indexFrequency = cursor.getColumnIndex(Words.FREQUENCY);
+            while (!cursor.isAfterLast()) {
+                final String word = cursor.getString(indexWord);
+                final int frequency = cursor.getInt(indexFrequency);
+                final int adjustedFrequency = scaleFrequencyFromDefaultToLatinIme(frequency);
+                // Safeguard against adding really long words.
+                if (word.length() <= MAX_WORD_LENGTH) {
+                    runGCIfRequiredLocked(true /* mindsBlockByGC */);
+                    addUnigramLocked(word, adjustedFrequency, false /* isNotAWord */,
+                            false /* isPossiblyOffensive */,
+                            BinaryDictionary.NOT_A_VALID_TIMESTAMP);
+                }
+                cursor.moveToNext();
+            }
+        }
+    }
+}