diff --git a/java/src/com/android/inputmethod/latin/makedict/DynamicBinaryDictIOUtils.java b/java/src/com/android/inputmethod/latin/makedict/DynamicBinaryDictIOUtils.java
deleted file mode 100644
index 97ad667..0000000
--- a/java/src/com/android/inputmethod/latin/makedict/DynamicBinaryDictIOUtils.java
+++ /dev/null
@@ -1,492 +0,0 @@
-/*
- * Copyright (C) 2013 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.inputmethod.latin.makedict;
-
-import com.android.inputmethod.annotations.UsedForTesting;
-import com.android.inputmethod.latin.Constants;
-import com.android.inputmethod.latin.makedict.BinaryDictDecoderUtils.DictBuffer;
-import com.android.inputmethod.latin.makedict.FormatSpec.FileHeader;
-import com.android.inputmethod.latin.makedict.FormatSpec.FormatOptions;
-import com.android.inputmethod.latin.makedict.FusionDictionary.WeightedString;
-import com.android.inputmethod.latin.utils.CollectionUtils;
-
-import java.io.IOException;
-import java.io.OutputStream;
-import java.util.ArrayList;
-import java.util.Arrays;
-
-/**
- * The utility class to help dynamic updates on the binary dictionary.
- *
- * All the methods in this class are static.
- */
-@UsedForTesting
-public final class DynamicBinaryDictIOUtils {
-    private static final boolean DBG = false;
-    static final int MAX_JUMPS = 10000;
-
-    private DynamicBinaryDictIOUtils() {
-        // This utility class is not publicly instantiable.
-    }
-
-    /* package */ static int markAsDeleted(final int flags) {
-        return (flags & (~FormatSpec.MASK_CHILDREN_ADDRESS_TYPE)) | FormatSpec.FLAG_IS_DELETED;
-    }
-
-    /**
-     * Update a parent address in a PtNode that is referred to by ptNodeOriginAddress.
-     *
-     * @param dictUpdater the DictUpdater to write.
-     * @param ptNodeOriginAddress the address of the PtNode.
-     * @param newParentAddress the absolute address of the parent.
-     * @param formatOptions file format options.
-     */
-    private static void updateParentAddress(final Ver2DictUpdater dictUpdater,
-            final int ptNodeOriginAddress, final int newParentAddress,
-            final FormatOptions formatOptions) {
-        final DictBuffer dictBuffer = dictUpdater.getDictBuffer();
-        final int originalPosition = dictBuffer.position();
-        dictBuffer.position(ptNodeOriginAddress);
-        if (!formatOptions.supportsDynamicUpdate()) {
-            throw new RuntimeException("this file format does not support parent addresses");
-        }
-        final int flags = dictBuffer.readUnsignedByte();
-        if (BinaryDictIOUtils.isMovedPtNode(flags, formatOptions)) {
-            // If the node is moved, the parent address is stored in the destination node.
-            // We are guaranteed to process the destination node later, so there is no need to
-            // update anything here.
-            dictBuffer.position(originalPosition);
-            return;
-        }
-        if (DBG) {
-            MakedictLog.d("update parent address flags=" + flags + ", " + ptNodeOriginAddress);
-        }
-        final int parentOffset = newParentAddress - ptNodeOriginAddress;
-        BinaryDictIOUtils.writeSInt24ToBuffer(dictBuffer, parentOffset);
-        dictBuffer.position(originalPosition);
-    }
-
-    /**
-     * Update parent addresses in a node array stored at ptNodeOriginAddress.
-     *
-     * @param dictUpdater the DictUpdater to be modified.
-     * @param ptNodeOriginAddress the address of the node array to update.
-     * @param newParentAddress the address to be written.
-     * @param formatOptions file format options.
-     */
-    private static void updateParentAddresses(final Ver2DictUpdater dictUpdater,
-            final int ptNodeOriginAddress, final int newParentAddress,
-            final FormatOptions formatOptions) {
-        final int originalPosition = dictUpdater.getPosition();
-        dictUpdater.setPosition(ptNodeOriginAddress);
-        do {
-            final int count = dictUpdater.readPtNodeCount();
-            for (int i = 0; i < count; ++i) {
-                updateParentAddress(dictUpdater, dictUpdater.getPosition(), newParentAddress,
-                        formatOptions);
-                dictUpdater.skipPtNode(formatOptions);
-            }
-            if (!dictUpdater.readAndFollowForwardLink()) break;
-            if (dictUpdater.getPosition() == FormatSpec.NO_FORWARD_LINK_ADDRESS) break;
-        } while (formatOptions.supportsDynamicUpdate());
-        dictUpdater.setPosition(originalPosition);
-    }
-
-    /**
-     * Update a children address in a PtNode that is addressed by ptNodeOriginAddress.
-     *
-     * @param dictUpdater the DictUpdater to write.
-     * @param ptNodeOriginAddress the address of the PtNode.
-     * @param newChildrenAddress the absolute address of the child.
-     * @param formatOptions file format options.
-     */
-    private static void updateChildrenAddress(final Ver2DictUpdater dictUpdater,
-            final int ptNodeOriginAddress, final int newChildrenAddress,
-            final FormatOptions formatOptions) {
-        final DictBuffer dictBuffer = dictUpdater.getDictBuffer();
-        final int originalPosition = dictBuffer.position();
-        dictBuffer.position(ptNodeOriginAddress);
-        final int flags = dictBuffer.readUnsignedByte();
-        BinaryDictDecoderUtils.readParentAddress(dictBuffer, formatOptions);
-        BinaryDictIOUtils.skipString(dictBuffer, (flags & FormatSpec.FLAG_HAS_MULTIPLE_CHARS) != 0);
-        if ((flags & FormatSpec.FLAG_IS_TERMINAL) != 0) dictBuffer.readUnsignedByte();
-        final int childrenOffset = newChildrenAddress == FormatSpec.NO_CHILDREN_ADDRESS
-                ? FormatSpec.NO_CHILDREN_ADDRESS : newChildrenAddress - dictBuffer.position();
-        BinaryDictIOUtils.writeSInt24ToBuffer(dictBuffer, childrenOffset);
-        dictBuffer.position(originalPosition);
-    }
-
-    /**
-     * Helper method to move a PtNode to the tail of the file.
-     */
-    private static int movePtNode(final OutputStream destination,
-            final Ver2DictUpdater dictUpdater, final PtNodeInfo info,
-            final int nodeArrayOriginAddress, final int oldNodeAddress,
-            final FormatOptions formatOptions) throws IOException {
-        final DictBuffer dictBuffer = dictUpdater.getDictBuffer();
-        updateParentAddress(dictUpdater, oldNodeAddress, dictBuffer.limit() + 1, formatOptions);
-        dictBuffer.position(oldNodeAddress);
-        final int currentFlags = dictBuffer.readUnsignedByte();
-        dictBuffer.position(oldNodeAddress);
-        dictBuffer.put((byte)(FormatSpec.FLAG_IS_MOVED | (currentFlags
-                & (~FormatSpec.MASK_MOVE_AND_DELETE_FLAG))));
-        int size = FormatSpec.PTNODE_FLAGS_SIZE;
-        updateForwardLink(dictUpdater, nodeArrayOriginAddress, dictBuffer.limit(), formatOptions);
-        size += BinaryDictIOUtils.writeNodes(destination, new PtNodeInfo[] { info });
-        return size;
-    }
-
-    @SuppressWarnings("unused")
-    private static void updateForwardLink(final Ver2DictUpdater dictUpdater,
-            final int nodeArrayOriginAddress, final int newNodeArrayAddress,
-            final FormatOptions formatOptions) {
-        final DictBuffer dictBuffer = dictUpdater.getDictBuffer();
-        dictUpdater.setPosition(nodeArrayOriginAddress);
-        int jumpCount = 0;
-        while (jumpCount++ < MAX_JUMPS) {
-            final int count = dictUpdater.readPtNodeCount();
-            for (int i = 0; i < count; ++i) {
-                dictUpdater.readPtNode(dictUpdater.getPosition(), formatOptions);
-            }
-            final int forwardLinkAddress = dictBuffer.readUnsignedInt24();
-            if (forwardLinkAddress == FormatSpec.NO_FORWARD_LINK_ADDRESS) {
-                dictBuffer.position(dictBuffer.position() - FormatSpec.FORWARD_LINK_ADDRESS_SIZE);
-                BinaryDictIOUtils.writeSInt24ToBuffer(dictBuffer, newNodeArrayAddress);
-                return;
-            }
-            dictBuffer.position(forwardLinkAddress);
-        }
-        if (DBG && jumpCount >= MAX_JUMPS) {
-            throw new RuntimeException("too many jumps, probably a bug.");
-        }
-    }
-
-    /**
-     * Move a PtNode that is referred to by oldPtNodeOrigin to the tail of the file, and set the
-     * children address to the byte after the PtNode.
-     *
-     * @param fileEndAddress the address of the tail of the file.
-     * @param codePoints the characters to put inside the PtNode.
-     * @param length how many code points to read from codePoints.
-     * @param flags the flags for this PtNode.
-     * @param frequency the frequency of this terminal.
-     * @param parentAddress the address of the parent PtNode of this PtNode.
-     * @param shortcutTargets the shortcut targets for this PtNode.
-     * @param bigrams the bigrams for this PtNode.
-     * @param destination the stream representing the tail of the file.
-     * @param dictUpdater the DictUpdater.
-     * @param oldPtNodeArrayOrigin the origin of the old PtNode array this PtNode was a part of.
-     * @param oldPtNodeOrigin the old origin where this PtNode used to be stored.
-     * @param formatOptions format options for this dictionary.
-     * @return the size written, in bytes.
-     * @throws IOException if the file can't be accessed
-     */
-    private static int movePtNode(final int fileEndAddress, final int[] codePoints,
-            final int length, final int flags, final int frequency, final int parentAddress,
-            final ArrayList<WeightedString> shortcutTargets,
-            final ArrayList<PendingAttribute> bigrams, final OutputStream destination,
-            final Ver2DictUpdater dictUpdater, final int oldPtNodeArrayOrigin,
-            final int oldPtNodeOrigin, final FormatOptions formatOptions) throws IOException {
-        int size = 0;
-        final int newPtNodeOrigin = fileEndAddress + 1;
-        final int[] writtenCharacters = Arrays.copyOfRange(codePoints, 0, length);
-        final PtNodeInfo tmpInfo = new PtNodeInfo(newPtNodeOrigin, -1 /* endAddress */,
-                flags, writtenCharacters, frequency, parentAddress, FormatSpec.NO_CHILDREN_ADDRESS,
-                shortcutTargets, bigrams);
-        size = BinaryDictIOUtils.computePtNodeSize(tmpInfo, formatOptions);
-        final PtNodeInfo newInfo = new PtNodeInfo(newPtNodeOrigin, newPtNodeOrigin + size,
-                flags, writtenCharacters, frequency, parentAddress,
-                fileEndAddress + 1 + size + FormatSpec.FORWARD_LINK_ADDRESS_SIZE, shortcutTargets,
-                bigrams);
-        movePtNode(destination, dictUpdater, newInfo, oldPtNodeArrayOrigin, oldPtNodeOrigin,
-                formatOptions);
-        return 1 + size + FormatSpec.FORWARD_LINK_ADDRESS_SIZE;
-    }
-
-    /**
-     * Converts a list of WeightedString to a list of PendingAttribute.
-     */
-    public static ArrayList<PendingAttribute> resolveBigramPositions(final DictUpdater dictUpdater,
-            final ArrayList<WeightedString> bigramStrings)
-                    throws IOException, UnsupportedFormatException {
-        if (bigramStrings == null) return CollectionUtils.newArrayList();
-        final ArrayList<PendingAttribute> bigrams = CollectionUtils.newArrayList();
-        for (final WeightedString bigram : bigramStrings) {
-            final int pos = dictUpdater.getTerminalPosition(bigram.mWord);
-            if (pos == FormatSpec.NOT_VALID_WORD) {
-                // TODO: figure out what is the correct thing to do here.
-            } else {
-                bigrams.add(new PendingAttribute(bigram.mFrequency, pos));
-            }
-        }
-        return bigrams;
-    }
-
-    /**
-     * Insert a word into a binary dictionary.
-     *
-     * @param dictUpdater the dict updater.
-     * @param destination a stream to the underlying file, with the pointer at the end of the file.
-     * @param word the word to insert.
-     * @param frequency the frequency of the new word.
-     * @param bigramStrings bigram list, or null if none.
-     * @param shortcuts shortcut list, or null if none.
-     * @param isBlackListEntry whether this should be a blacklist entry.
-     * @throws IOException if the file can't be accessed.
-     * @throws UnsupportedFormatException if the existing dictionary is in an unexpected format.
-     */
-    // TODO: Support batch insertion.
-    // TODO: Remove @UsedForTesting once UserHistoryDictionary is implemented by BinaryDictionary.
-    @UsedForTesting
-    public static void insertWord(final Ver2DictUpdater dictUpdater,
-            final OutputStream destination, final String word, final int frequency,
-            final ArrayList<WeightedString> bigramStrings,
-            final ArrayList<WeightedString> shortcuts, final boolean isNotAWord,
-            final boolean isBlackListEntry)
-                    throws IOException, UnsupportedFormatException {
-        final ArrayList<PendingAttribute> bigrams = resolveBigramPositions(dictUpdater,
-                bigramStrings);
-        final DictBuffer dictBuffer = dictUpdater.getDictBuffer();
-
-        final boolean isTerminal = true;
-        final boolean hasBigrams = !bigrams.isEmpty();
-        final boolean hasShortcuts = shortcuts != null && !shortcuts.isEmpty();
-
-        // find the insert position of the word.
-        if (dictBuffer.position() != 0) dictBuffer.position(0);
-        final FileHeader fileHeader = dictUpdater.readHeader();
-
-        int wordPos = 0, address = dictBuffer.position(), nodeOriginAddress = dictBuffer.position();
-        final int[] codePoints = FusionDictionary.getCodePoints(word);
-        final int wordLen = codePoints.length;
-
-        for (int depth = 0; depth < Constants.DICTIONARY_MAX_WORD_LENGTH; ++depth) {
-            if (wordPos >= wordLen) break;
-            nodeOriginAddress = dictBuffer.position();
-            int nodeParentAddress = -1;
-            final int ptNodeCount = BinaryDictDecoderUtils.readPtNodeCount(dictBuffer);
-            boolean foundNextNode = false;
-
-            for (int i = 0; i < ptNodeCount; ++i) {
-                address = dictBuffer.position();
-                final PtNodeInfo currentInfo = dictUpdater.readPtNode(address,
-                        fileHeader.mFormatOptions);
-                final boolean isMovedNode = BinaryDictIOUtils.isMovedPtNode(currentInfo.mFlags,
-                        fileHeader.mFormatOptions);
-                if (isMovedNode) continue;
-                nodeParentAddress = (currentInfo.mParentAddress == FormatSpec.NO_PARENT_ADDRESS)
-                        ? FormatSpec.NO_PARENT_ADDRESS : currentInfo.mParentAddress + address;
-                boolean matched = true;
-                for (int p = 0; p < currentInfo.mCharacters.length; ++p) {
-                    if (wordPos + p >= wordLen) {
-                        /*
-                         * splitting
-                         * before
-                         *  abcd - ef
-                         *
-                         * insert "abc"
-                         *
-                         * after
-                         *  abc - d - ef
-                         */
-                        final int newNodeAddress = dictBuffer.limit();
-                        final int flags = BinaryDictEncoderUtils.makePtNodeFlags(p > 1,
-                                isTerminal, 0, hasShortcuts, hasBigrams, false /* isNotAWord */,
-                                false /* isBlackListEntry */, fileHeader.mFormatOptions);
-                        int written = movePtNode(newNodeAddress, currentInfo.mCharacters, p, flags,
-                                frequency, nodeParentAddress, shortcuts, bigrams, destination,
-                                dictUpdater, nodeOriginAddress, address, fileHeader.mFormatOptions);
-
-                        final int[] characters2 = Arrays.copyOfRange(currentInfo.mCharacters, p,
-                                currentInfo.mCharacters.length);
-                        if (currentInfo.mChildrenAddress != FormatSpec.NO_CHILDREN_ADDRESS) {
-                            updateParentAddresses(dictUpdater, currentInfo.mChildrenAddress,
-                                    newNodeAddress + written + 1, fileHeader.mFormatOptions);
-                        }
-                        final PtNodeInfo newInfo2 = new PtNodeInfo(
-                                newNodeAddress + written + 1, -1 /* endAddress */,
-                                currentInfo.mFlags, characters2, currentInfo.mFrequency,
-                                newNodeAddress + 1, currentInfo.mChildrenAddress,
-                                currentInfo.mShortcutTargets, currentInfo.mBigrams);
-                        BinaryDictIOUtils.writeNodes(destination, new PtNodeInfo[] { newInfo2 });
-                        return;
-                    } else if (codePoints[wordPos + p] != currentInfo.mCharacters[p]) {
-                        if (p > 0) {
-                            /*
-                             * splitting
-                             * before
-                             *   ab - cd
-                             *
-                             * insert "ac"
-                             *
-                             * after
-                             *   a - b - cd
-                             *     |
-                             *     - c
-                             */
-
-                            final int newNodeAddress = dictBuffer.limit();
-                            final int childrenAddress = currentInfo.mChildrenAddress;
-
-                            // move prefix
-                            final int prefixFlags = BinaryDictEncoderUtils.makePtNodeFlags(p > 1,
-                                    false /* isTerminal */, 0 /* childrenAddressSize*/,
-                                    false /* hasShortcut */, false /* hasBigrams */,
-                                    false /* isNotAWord */, false /* isBlackListEntry */,
-                                    fileHeader.mFormatOptions);
-                            int written = movePtNode(newNodeAddress, currentInfo.mCharacters, p,
-                                    prefixFlags, -1 /* frequency */, nodeParentAddress, null, null,
-                                    destination, dictUpdater, nodeOriginAddress, address,
-                                    fileHeader.mFormatOptions);
-
-                            final int[] suffixCharacters = Arrays.copyOfRange(
-                                    currentInfo.mCharacters, p, currentInfo.mCharacters.length);
-                            if (currentInfo.mChildrenAddress != FormatSpec.NO_CHILDREN_ADDRESS) {
-                                updateParentAddresses(dictUpdater, currentInfo.mChildrenAddress,
-                                        newNodeAddress + written + 1, fileHeader.mFormatOptions);
-                            }
-                            final int suffixFlags = BinaryDictEncoderUtils.makePtNodeFlags(
-                                    suffixCharacters.length > 1,
-                                    (currentInfo.mFlags & FormatSpec.FLAG_IS_TERMINAL) != 0,
-                                    0 /* childrenAddressSize */,
-                                    (currentInfo.mFlags & FormatSpec.FLAG_HAS_SHORTCUT_TARGETS)
-                                            != 0,
-                                    (currentInfo.mFlags & FormatSpec.FLAG_HAS_BIGRAMS) != 0,
-                                    isNotAWord, isBlackListEntry, fileHeader.mFormatOptions);
-                            final PtNodeInfo suffixInfo = new PtNodeInfo(
-                                    newNodeAddress + written + 1, -1 /* endAddress */, suffixFlags,
-                                    suffixCharacters, currentInfo.mFrequency, newNodeAddress + 1,
-                                    currentInfo.mChildrenAddress, currentInfo.mShortcutTargets,
-                                    currentInfo.mBigrams);
-                            written += BinaryDictIOUtils.computePtNodeSize(suffixInfo,
-                                    fileHeader.mFormatOptions) + 1;
-
-                            final int[] newCharacters = Arrays.copyOfRange(codePoints, wordPos + p,
-                                    codePoints.length);
-                            final int flags = BinaryDictEncoderUtils.makePtNodeFlags(
-                                    newCharacters.length > 1, isTerminal,
-                                    0 /* childrenAddressSize */, hasShortcuts, hasBigrams,
-                                    isNotAWord, isBlackListEntry, fileHeader.mFormatOptions);
-                            final PtNodeInfo newInfo = new PtNodeInfo(
-                                    newNodeAddress + written, -1 /* endAddress */, flags,
-                                    newCharacters, frequency, newNodeAddress + 1,
-                                    FormatSpec.NO_CHILDREN_ADDRESS, shortcuts, bigrams);
-                            BinaryDictIOUtils.writeNodes(destination,
-                                    new PtNodeInfo[] { suffixInfo, newInfo });
-                            return;
-                        }
-                        matched = false;
-                        break;
-                    }
-                }
-
-                if (matched) {
-                    if (wordPos + currentInfo.mCharacters.length == wordLen) {
-                        // the word exists in the dictionary.
-                        // only update the PtNode.
-                        final int newNodeAddress = dictBuffer.limit();
-                        final boolean hasMultipleChars = currentInfo.mCharacters.length > 1;
-                        final int flags = BinaryDictEncoderUtils.makePtNodeFlags(hasMultipleChars,
-                                isTerminal, 0 /* childrenAddressSize */, hasShortcuts, hasBigrams,
-                                isNotAWord, isBlackListEntry, fileHeader.mFormatOptions);
-                        final PtNodeInfo newInfo = new PtNodeInfo(newNodeAddress + 1,
-                                -1 /* endAddress */, flags, currentInfo.mCharacters, frequency,
-                                nodeParentAddress, currentInfo.mChildrenAddress, shortcuts,
-                                bigrams);
-                        movePtNode(destination, dictUpdater, newInfo, nodeOriginAddress, address,
-                                fileHeader.mFormatOptions);
-                        return;
-                    }
-                    wordPos += currentInfo.mCharacters.length;
-                    if (currentInfo.mChildrenAddress == FormatSpec.NO_CHILDREN_ADDRESS) {
-                        /*
-                         * found the prefix of the word.
-                         * make new PtNode and link to the PtNode from this PtNode.
-                         *
-                         * before
-                         * ab - cd
-                         *
-                         * insert "abcde"
-                         *
-                         * after
-                         * ab - cd - e
-                         */
-                        final int newNodeArrayAddress = dictBuffer.limit();
-                        updateChildrenAddress(dictUpdater, address, newNodeArrayAddress,
-                                fileHeader.mFormatOptions);
-                        final int newNodeAddress = newNodeArrayAddress + 1;
-                        final boolean hasMultipleChars = (wordLen - wordPos) > 1;
-                        final int flags = BinaryDictEncoderUtils.makePtNodeFlags(hasMultipleChars,
-                                isTerminal, 0 /* childrenAddressSize */, hasShortcuts, hasBigrams,
-                                isNotAWord, isBlackListEntry, fileHeader.mFormatOptions);
-                        final int[] characters = Arrays.copyOfRange(codePoints, wordPos, wordLen);
-                        final PtNodeInfo newInfo = new PtNodeInfo(newNodeAddress, -1, flags,
-                                characters, frequency, address, FormatSpec.NO_CHILDREN_ADDRESS,
-                                shortcuts, bigrams);
-                        BinaryDictIOUtils.writeNodes(destination, new PtNodeInfo[] { newInfo });
-                        return;
-                    }
-                    dictBuffer.position(currentInfo.mChildrenAddress);
-                    foundNextNode = true;
-                    break;
-                }
-            }
-
-            if (foundNextNode) continue;
-
-            // reached the end of the array.
-            final int linkAddressPosition = dictBuffer.position();
-            int nextLink = dictBuffer.readUnsignedInt24();
-            if ((nextLink & FormatSpec.MSB24) != 0) {
-                nextLink = -(nextLink & FormatSpec.SINT24_MAX);
-            }
-            if (nextLink == FormatSpec.NO_FORWARD_LINK_ADDRESS) {
-                /*
-                 * expand this node.
-                 *
-                 * before
-                 * ab - cd
-                 *
-                 * insert "abef"
-                 *
-                 * after
-                 * ab - cd
-                 *    |
-                 *    - ef
-                 */
-
-                // change the forward link address.
-                final int newNodeAddress = dictBuffer.limit();
-                dictBuffer.position(linkAddressPosition);
-                BinaryDictIOUtils.writeSInt24ToBuffer(dictBuffer, newNodeAddress);
-
-                final int[] characters = Arrays.copyOfRange(codePoints, wordPos, wordLen);
-                final int flags = BinaryDictEncoderUtils.makePtNodeFlags(characters.length > 1,
-                        isTerminal, 0 /* childrenAddressSize */, hasShortcuts, hasBigrams,
-                        isNotAWord, isBlackListEntry, fileHeader.mFormatOptions);
-                final PtNodeInfo newInfo = new PtNodeInfo(newNodeAddress + 1,
-                        -1 /* endAddress */, flags, characters, frequency, nodeParentAddress,
-                        FormatSpec.NO_CHILDREN_ADDRESS, shortcuts, bigrams);
-                BinaryDictIOUtils.writeNodes(destination, new PtNodeInfo[]{ newInfo });
-                return;
-            } else {
-                depth--;
-                dictBuffer.position(nextLink);
-            }
-        }
-    }
-}
diff --git a/java/src/com/android/inputmethod/latin/makedict/Ver2DictUpdater.java b/java/src/com/android/inputmethod/latin/makedict/Ver2DictUpdater.java
deleted file mode 100644
index 6419340..0000000
--- a/java/src/com/android/inputmethod/latin/makedict/Ver2DictUpdater.java
+++ /dev/null
@@ -1,82 +0,0 @@
-/*
- * Copyright (C) 2013 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.inputmethod.latin.makedict;
-
-import com.android.inputmethod.annotations.UsedForTesting;
-import com.android.inputmethod.latin.makedict.FusionDictionary.WeightedString;
-
-import java.io.File;
-import java.io.FileNotFoundException;
-import java.io.FileOutputStream;
-import java.io.IOException;
-import java.io.OutputStream;
-import java.util.ArrayList;
-
-/**
- * An implementation of DictUpdater for version 2 binary dictionary.
- */
-@UsedForTesting
-public class Ver2DictUpdater extends Ver2DictDecoder implements DictUpdater {
-    private OutputStream mOutStream;
-
-    @UsedForTesting
-    public Ver2DictUpdater(final File dictFile, final int factoryType) {
-        // DictUpdater must have an updatable DictBuffer.
-        super(dictFile, ((factoryType & MASK_DICTBUFFER) == USE_BYTEARRAY)
-                ? USE_BYTEARRAY : USE_WRITABLE_BYTEBUFFER);
-        mOutStream = null;
-    }
-
-    private void openStreamAndBuffer() throws FileNotFoundException, IOException {
-        super.openDictBuffer();
-        mOutStream = new FileOutputStream(mDictionaryBinaryFile, true /* append */);
-    }
-
-    private void close() throws IOException {
-        if (mOutStream != null) {
-            mOutStream.close();
-            mOutStream = null;
-        }
-    }
-
-    @Override @UsedForTesting
-    public void deleteWord(final String word) throws IOException, UnsupportedFormatException {
-        if (mOutStream == null) openStreamAndBuffer();
-        mDictBuffer.position(0);
-        readHeader();
-        final int wordPos = getTerminalPosition(word);
-        if (wordPos != FormatSpec.NOT_VALID_WORD) {
-            mDictBuffer.position(wordPos);
-            final int flags = mDictBuffer.readUnsignedByte();
-            mDictBuffer.position(wordPos);
-            mDictBuffer.put((byte) DynamicBinaryDictIOUtils.markAsDeleted(flags));
-        }
-        close();
-    }
-
-    @Override @UsedForTesting
-    public void insertWord(final String word, final int frequency,
-            final ArrayList<WeightedString> bigramStrings,
-            final ArrayList<WeightedString> shortcuts,
-            final boolean isNotAWord, final boolean isBlackListEntry)
-                    throws IOException, UnsupportedFormatException {
-        if (mOutStream == null) openStreamAndBuffer();
-        DynamicBinaryDictIOUtils.insertWord(this, mOutStream, word, frequency, bigramStrings,
-                shortcuts, isNotAWord, isBlackListEntry);
-        close();
-    }
-}
diff --git a/java/src/com/android/inputmethod/latin/makedict/Ver4DictUpdater.java b/java/src/com/android/inputmethod/latin/makedict/Ver4DictUpdater.java
index c46bc36..6298295 100644
--- a/java/src/com/android/inputmethod/latin/makedict/Ver4DictUpdater.java
+++ b/java/src/com/android/inputmethod/latin/makedict/Ver4DictUpdater.java
@@ -40,6 +40,7 @@
 @UsedForTesting
 public class Ver4DictUpdater extends Ver4DictDecoder implements DictUpdater {
     private static final String TAG = Ver4DictUpdater.class.getSimpleName();
+    private static final int MAX_JUMPS = 10000;
 
     private OutputStream mDictStream;
     private final File mFrequencyFile;
@@ -146,7 +147,7 @@
             mDictBuffer.position(wordPos);
             final int flags = PtNodeReader.readPtNodeOptionFlags(mDictBuffer);
             mDictBuffer.position(wordPos);
-            mDictBuffer.put((byte) DynamicBinaryDictIOUtils.markAsDeleted(flags));
+            mDictBuffer.put((byte)markAsDeleted(flags));
         }
     }
 
@@ -183,7 +184,7 @@
                 skipPtNode(formatOptions);
             }
             if (!readAndFollowForwardLink()) break;
-        } while (jumpCount++ < DynamicBinaryDictIOUtils.MAX_JUMPS);
+        } while (jumpCount++ < MAX_JUMPS);
         setPosition(originalPos);
     }
 
@@ -216,7 +217,7 @@
         final int originalPos = getPosition();
         setPosition(nodeArrayPos);
         int jumpCount = 0;
-        while (jumpCount++ < DynamicBinaryDictIOUtils.MAX_JUMPS) {
+        while (jumpCount++ < MAX_JUMPS) {
             final int ptNodeCount = readPtNodeCount();
             for (int i = 0; i < ptNodeCount; ++i) {
                 skipPtNode(formatOptions);
@@ -735,8 +736,7 @@
         mDictBuffer.put((byte) newFlags);
 
         updateFrequency(terminalId, frequency);
-        insertBigrams(terminalId, frequency,
-                DynamicBinaryDictIOUtils.resolveBigramPositions(this, bigramStrings));
+        insertBigrams(terminalId, frequency, resolveBigramPositions(this, bigramStrings));
         insertShortcuts(terminalId, shortcuts);
     }
 
@@ -765,8 +765,30 @@
         insertTerminalPosition(posOfTerminal);
         close();
 
-        insertBigrams(newTerminalId, frequency,
-                DynamicBinaryDictIOUtils.resolveBigramPositions(this, bigramStrings));
+        insertBigrams(newTerminalId, frequency, resolveBigramPositions(this, bigramStrings));
         insertShortcuts(newTerminalId, shortcuts);
     }
+
+    /**
+     * Converts a list of WeightedString to a list of PendingAttribute.
+     */
+    private static ArrayList<PendingAttribute> resolveBigramPositions(final DictUpdater dictUpdater,
+            final ArrayList<WeightedString> bigramStrings)
+                    throws IOException, UnsupportedFormatException {
+        if (bigramStrings == null) return CollectionUtils.newArrayList();
+        final ArrayList<PendingAttribute> bigrams = CollectionUtils.newArrayList();
+        for (final WeightedString bigram : bigramStrings) {
+            final int pos = dictUpdater.getTerminalPosition(bigram.mWord);
+            if (pos == FormatSpec.NOT_VALID_WORD) {
+                // TODO: figure out what is the correct thing to do here.
+            } else {
+                bigrams.add(new PendingAttribute(bigram.mFrequency, pos));
+            }
+        }
+        return bigrams;
+    }
+
+    private static int markAsDeleted(final int flags) {
+        return (flags & (~FormatSpec.MASK_CHILDREN_ADDRESS_TYPE)) | FormatSpec.FLAG_IS_DELETED;
+    }
 }
diff --git a/tests/src/com/android/inputmethod/latin/makedict/BinaryDictUtils.java b/tests/src/com/android/inputmethod/latin/makedict/BinaryDictUtils.java
index 208cb99..a568704 100644
--- a/tests/src/com/android/inputmethod/latin/makedict/BinaryDictUtils.java
+++ b/tests/src/com/android/inputmethod/latin/makedict/BinaryDictUtils.java
@@ -76,8 +76,6 @@
             throws UnsupportedFormatException {
         if (formatOptions.mVersion == FormatSpec.VERSION4) {
             return new Ver4DictUpdater(file, DictDecoder.USE_WRITABLE_BYTEBUFFER);
-        } else if (formatOptions.mVersion == FormatSpec.VERSION3) {
-            return new Ver2DictUpdater(file, DictDecoder.USE_WRITABLE_BYTEBUFFER);
         } else {
             throw new UnsupportedFormatException("The format option has a wrong version : "
                     + formatOptions.mVersion);