From 203dcfe2c3d63f0e6ff79c2c5566115c2571a35c Mon Sep 17 00:00:00 2001
From: Art O Cathain <art.home@gmail.com>
Date: Sat, 4 Oct 2014 11:45:45 +0100
Subject: [PATCH] use interfaces, not implementions

---
 src/com/fsck/k9/Account.java                  |  2 +-
 src/com/fsck/k9/K9.java                       |  3 +-
 .../AccessibleEmailContentActivity.java       |  6 +-
 src/com/fsck/k9/activity/Accounts.java        |  8 +-
 src/com/fsck/k9/activity/FolderList.java      |  6 +-
 .../fsck/k9/activity/FolderListFilter.java    |  8 +-
 src/com/fsck/k9/activity/MessageCompose.java  | 10 +-
 .../NotificationDeleteConfirmation.java       |  8 +-
 .../k9/controller/MessagingController.java    | 36 +++----
 .../fsck/k9/fragment/MessageListFragment.java |  4 +-
 src/com/fsck/k9/helper/Contacts.java          |  3 +-
 src/com/fsck/k9/helper/Utility.java           | 22 +++++
 src/com/fsck/k9/mail/Address.java             |  2 +-
 src/com/fsck/k9/mail/Multipart.java           |  2 +-
 src/com/fsck/k9/mail/Store.java               |  8 +-
 src/com/fsck/k9/mail/internet/MimeHeader.java |  6 +-
 src/com/fsck/k9/mail/store/ImapStore.java     | 20 ++--
 src/com/fsck/k9/mail/store/Pop3Store.java     | 16 ++--
 src/com/fsck/k9/mail/store/WebDavStore.java   | 94 +++++++++----------
 .../fsck/k9/mail/store/imap/ImapUtility.java  |  4 +-
 .../fsck/k9/mail/store/local/LocalFolder.java |  2 +-
 .../k9/mail/store/local/LocalMessage.java     |  3 +-
 .../fsck/k9/mail/store/local/LocalStore.java  | 10 +-
 .../fsck/k9/mail/transport/SmtpTransport.java | 22 ++---
 src/com/fsck/k9/preferences/Editor.java       |  5 +-
 src/com/fsck/k9/preferences/Storage.java      | 24 +++--
 .../fsck/k9/search/ConditionsTreeNode.java    |  2 +-
 src/com/fsck/k9/search/LocalSearch.java       |  2 +-
 .../k9/service/NotificationActionService.java | 20 ++--
 src/com/fsck/k9/service/PollService.java      |  3 +-
 .../fsck/k9/view/NonLockingScrollView.java    |  5 +-
 31 files changed, 205 insertions(+), 161 deletions(-)

diff --git a/src/com/fsck/k9/Account.java b/src/com/fsck/k9/Account.java
index 323d53762..faf9d1e7c 100644
--- a/src/com/fsck/k9/Account.java
+++ b/src/com/fsck/k9/Account.java
@@ -181,7 +181,7 @@ public class Account implements BaseAccount {
     private boolean mPushPollOnConnect;
     private boolean mNotifySync;
     private SortType mSortType;
-    private HashMap<SortType, Boolean> mSortAscending = new HashMap<SortType, Boolean>();
+    private Map<SortType, Boolean> mSortAscending = new HashMap<SortType, Boolean>();
     private ShowPictures mShowPictures;
     private boolean mIsSignatureBeforeQuotedText;
     private String mExpungePolicy = EXPUNGE_IMMEDIATELY;
diff --git a/src/com/fsck/k9/K9.java b/src/com/fsck/k9/K9.java
index 9eead455a..6b5d83d56 100644
--- a/src/com/fsck/k9/K9.java
+++ b/src/com/fsck/k9/K9.java
@@ -5,6 +5,7 @@ import java.io.File;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.concurrent.BlockingQueue;
 import java.util.concurrent.SynchronousQueue;
 
@@ -263,7 +264,7 @@ public class K9 extends Application {
     private static boolean mHideTimeZone = false;
 
     private static SortType mSortType;
-    private static HashMap<SortType, Boolean> mSortAscending = new HashMap<SortType, Boolean>();
+    private static Map<SortType, Boolean> mSortAscending = new HashMap<SortType, Boolean>();
 
     private static boolean sUseBackgroundAsUnreadIndicator = true;
     private static boolean sThreadedViewEnabled = true;
diff --git a/src/com/fsck/k9/activity/AccessibleEmailContentActivity.java b/src/com/fsck/k9/activity/AccessibleEmailContentActivity.java
index 4b62641e4..b81c0cb09 100644
--- a/src/com/fsck/k9/activity/AccessibleEmailContentActivity.java
+++ b/src/com/fsck/k9/activity/AccessibleEmailContentActivity.java
@@ -17,6 +17,8 @@
 package com.fsck.k9.activity;
 
 import java.util.ArrayList;
+import java.util.List;
+
 import android.app.ListActivity;
 import android.os.Bundle;
 import android.text.Html;
@@ -40,7 +42,7 @@ public class AccessibleEmailContentActivity extends ListActivity {
         Spanned parsedHtml = Html.fromHtml(htmlSource, null, null);
         String[] rawListItems = parsedHtml.toString().split("\n");
 
-        ArrayList<String> cleanedList = new ArrayList<String>();
+        List<String> cleanedList = new ArrayList<String>();
         for (String rawListItem : rawListItems) {
             if (rawListItem.trim().length() > 0) {
                 addToCleanedList(cleanedList, rawListItem);
@@ -53,7 +55,7 @@ public class AccessibleEmailContentActivity extends ListActivity {
         setListAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, listItems));
     }
 
-    private void addToCleanedList(ArrayList<String> cleanedList, String line) {
+    private void addToCleanedList(List<String> cleanedList, String line) {
         if (line.length() < 80) {
             cleanedList.add(line);
         } else {
diff --git a/src/com/fsck/k9/activity/Accounts.java b/src/com/fsck/k9/activity/Accounts.java
index 76cfe3abb..0b9a76f06 100644
--- a/src/com/fsck/k9/activity/Accounts.java
+++ b/src/com/fsck/k9/activity/Accounts.java
@@ -13,6 +13,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
 
 import android.app.ActionBar;
 import android.app.Activity;
@@ -75,6 +76,7 @@ import com.fsck.k9.activity.setup.Prefs;
 import com.fsck.k9.activity.setup.WelcomeMessage;
 import com.fsck.k9.controller.MessagingController;
 import com.fsck.k9.helper.SizeFormatter;
+import com.fsck.k9.helper.Utility;
 import com.fsck.k9.mail.AuthType;
 import com.fsck.k9.mail.ServerSettings;
 import com.fsck.k9.mail.Store;
@@ -120,9 +122,9 @@ public class Accounts extends K9ListActivity implements OnItemClickListener {
     private static final int DIALOG_RECREATE_ACCOUNT = 3;
     private static final int DIALOG_NO_FILE_MANAGER = 4;
 
-    private ConcurrentHashMap<String, AccountStats> accountStats = new ConcurrentHashMap<String, AccountStats>();
+    private ConcurrentMap<String, AccountStats> accountStats = new ConcurrentHashMap<String, AccountStats>();
 
-    private ConcurrentHashMap<BaseAccount, String> pendingWork = new ConcurrentHashMap<BaseAccount, String>();
+    private ConcurrentMap<BaseAccount, String> pendingWork = new ConcurrentHashMap<BaseAccount, String>();
 
     private BaseAccount mSelectedContextAccount;
     private int mUnreadMessageCount = 0;
@@ -495,7 +497,7 @@ public class Accounts extends K9ListActivity implements OnItemClickListener {
             outState.putString(SELECTED_CONTEXT_ACCOUNT, mSelectedContextAccount.getUuid());
         }
         outState.putSerializable(STATE_UNREAD_COUNT, mUnreadMessageCount);
-        outState.putSerializable(ACCOUNT_STATS, accountStats);
+        outState.putSerializable(ACCOUNT_STATS, Utility.toSerializableConcurrentMap(accountStats));
     }
 
     private StorageManager.StorageListener storageListener = new StorageManager.StorageListener() {
diff --git a/src/com/fsck/k9/activity/FolderList.java b/src/com/fsck/k9/activity/FolderList.java
index bd5be538b..217658b33 100644
--- a/src/com/fsck/k9/activity/FolderList.java
+++ b/src/com/fsck/k9/activity/FolderList.java
@@ -660,7 +660,7 @@ public class FolderList extends K9ListActivity {
     }
 
     class FolderListAdapter extends BaseAdapter implements Filterable {
-        private ArrayList<FolderInfoHolder> mFolders = new ArrayList<FolderInfoHolder>();
+        private List<FolderInfoHolder> mFolders = new ArrayList<FolderInfoHolder>();
         private List<FolderInfoHolder> mFilteredFolders = Collections.unmodifiableList(mFolders);
         private Filter mFilter = new FolderListFilter();
 
@@ -1176,7 +1176,7 @@ public class FolderList extends K9ListActivity {
 
                 Locale locale = Locale.getDefault();
                 if ((searchTerm == null) || (searchTerm.length() == 0)) {
-                    ArrayList<FolderInfoHolder> list = new ArrayList<FolderInfoHolder>(mFolders);
+                    List<FolderInfoHolder> list = new ArrayList<FolderInfoHolder>(mFolders);
                     results.values = list;
                     results.count = list.size();
                 } else {
@@ -1184,7 +1184,7 @@ public class FolderList extends K9ListActivity {
                     final String[] words = searchTermString.split(" ");
                     final int wordCount = words.length;
 
-                    final ArrayList<FolderInfoHolder> newValues = new ArrayList<FolderInfoHolder>();
+                    final List<FolderInfoHolder> newValues = new ArrayList<FolderInfoHolder>();
 
                     for (final FolderInfoHolder value : mFolders) {
                         if (value.displayName == null) {
diff --git a/src/com/fsck/k9/activity/FolderListFilter.java b/src/com/fsck/k9/activity/FolderListFilter.java
index 30a012600..ec01589c3 100644
--- a/src/com/fsck/k9/activity/FolderListFilter.java
+++ b/src/com/fsck/k9/activity/FolderListFilter.java
@@ -29,7 +29,7 @@ public class FolderListFilter<T> extends Filter {
     /**
      * All folders.
      */
-    private ArrayList<T> mOriginalValues = null;
+    private List<T> mOriginalValues = null;
 
     /**
      * Create a filter for a list of folders.
@@ -62,7 +62,7 @@ public class FolderListFilter<T> extends Filter {
 
         Locale locale = Locale.getDefault();
         if ((searchTerm == null) || (searchTerm.length() == 0)) {
-            ArrayList<T> list = new ArrayList<T>(mOriginalValues);
+            List<T> list = new ArrayList<T>(mOriginalValues);
             results.values = list;
             results.count = list.size();
         } else {
@@ -70,9 +70,9 @@ public class FolderListFilter<T> extends Filter {
             final String[] words = searchTermString.split(" ");
             final int wordCount = words.length;
 
-            final ArrayList<T> values = mOriginalValues;
+            final List<T> values = mOriginalValues;
 
-            final ArrayList<T> newValues = new ArrayList<T>();
+            final List<T> newValues = new ArrayList<T>();
 
             for (final T value : values) {
                 final String valueText = value.toString().toLowerCase(locale);
diff --git a/src/com/fsck/k9/activity/MessageCompose.java b/src/com/fsck/k9/activity/MessageCompose.java
index 05170db2e..4a0ab4cfa 100644
--- a/src/com/fsck/k9/activity/MessageCompose.java
+++ b/src/com/fsck/k9/activity/MessageCompose.java
@@ -1013,7 +1013,7 @@ public class MessageCompose extends K9Activity implements OnClickListener,
                     addAttachment(stream, type);
                 }
             } else {
-                ArrayList<Parcelable> list = intent.getParcelableArrayListExtra(Intent.EXTRA_STREAM);
+                List<Parcelable> list = intent.getParcelableArrayListExtra(Intent.EXTRA_STREAM);
                 if (list != null) {
                     for (Parcelable parcelable : list) {
                         Uri stream = (Uri) parcelable;
@@ -1155,7 +1155,7 @@ public class MessageCompose extends K9Activity implements OnClickListener,
     @Override
     protected void onSaveInstanceState(Bundle outState) {
         super.onSaveInstanceState(outState);
-        ArrayList<Attachment> attachments = new ArrayList<Attachment>();
+        List<Attachment> attachments = new ArrayList<Attachment>();
         for (int i = 0, count = mAttachments.getChildCount(); i < count; i++) {
             View view = mAttachments.getChildAt(i);
             Attachment attachment = (Attachment) view.getTag();
@@ -1164,7 +1164,7 @@ public class MessageCompose extends K9Activity implements OnClickListener,
 
         outState.putInt(STATE_KEY_NUM_ATTACHMENTS_LOADING, mNumAttachmentsLoading);
         outState.putString(STATE_KEY_WAITING_FOR_ATTACHMENTS, mWaitingForAttachments.name());
-        outState.putParcelableArrayList(STATE_KEY_ATTACHMENTS, attachments);
+        outState.putParcelableArrayList(STATE_KEY_ATTACHMENTS, Utility.toArrayList(attachments));
         outState.putBoolean(STATE_KEY_CC_SHOWN, mCcWrapper.getVisibility() == View.VISIBLE);
         outState.putBoolean(STATE_KEY_BCC_SHOWN, mBccWrapper.getVisibility() == View.VISIBLE);
         outState.putSerializable(STATE_KEY_QUOTED_TEXT_MODE, mQuotedTextMode);
@@ -1199,7 +1199,7 @@ public class MessageCompose extends K9Activity implements OnClickListener,
                     "\" from saved instance state", e);
         }
 
-        ArrayList<Attachment> attachments = savedInstanceState.getParcelableArrayList(STATE_KEY_ATTACHMENTS);
+        List<Attachment> attachments = savedInstanceState.getParcelableArrayList(STATE_KEY_ATTACHMENTS);
         for (Attachment attachment : attachments) {
             addAttachmentView(attachment);
             if (attachment.loaderId > mMaxLoaderId) {
@@ -1808,7 +1808,7 @@ public class MessageCompose extends K9Activity implements OnClickListener,
                 String[] emailsArray = null;
                 if (mEncryptCheckbox.isChecked()) {
                     // get emails as array
-                    ArrayList<String> emails = new ArrayList<String>();
+                    List<String> emails = new ArrayList<String>();
 
                     for (Address address : getRecipientAddresses()) {
                         emails.add(address.getAddress());
diff --git a/src/com/fsck/k9/activity/NotificationDeleteConfirmation.java b/src/com/fsck/k9/activity/NotificationDeleteConfirmation.java
index a740768c6..9a070ed39 100644
--- a/src/com/fsck/k9/activity/NotificationDeleteConfirmation.java
+++ b/src/com/fsck/k9/activity/NotificationDeleteConfirmation.java
@@ -1,6 +1,7 @@
 package com.fsck.k9.activity;
 
 import java.util.ArrayList;
+import java.util.List;
 
 import android.app.Activity;
 import android.app.AlertDialog;
@@ -14,6 +15,7 @@ import com.fsck.k9.Account;
 import com.fsck.k9.K9;
 import com.fsck.k9.Preferences;
 import com.fsck.k9.R;
+import com.fsck.k9.helper.Utility;
 import com.fsck.k9.service.NotificationActionService;
 
 public class NotificationDeleteConfirmation extends Activity {
@@ -23,12 +25,12 @@ public class NotificationDeleteConfirmation extends Activity {
     private final static int DIALOG_CONFIRM = 1;
 
     private Account mAccount;
-    private ArrayList<MessageReference> mMessageRefs;
+    private List<MessageReference> mMessageRefs;
 
-    public static PendingIntent getIntent(Context context, final Account account, final ArrayList<MessageReference> refs) {
+    public static PendingIntent getIntent(Context context, final Account account, final List<MessageReference> refs) {
         Intent i = new Intent(context, NotificationDeleteConfirmation.class);
         i.putExtra(EXTRA_ACCOUNT, account.getUuid());
-        i.putExtra(EXTRA_MESSAGE_LIST, refs);
+        i.putExtra(EXTRA_MESSAGE_LIST, Utility.toSerializableList(refs));
         i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TOP);
 
         return PendingIntent.getActivity(context, account.getAccountNumber(), i, PendingIntent.FLAG_UPDATE_CURRENT);
diff --git a/src/com/fsck/k9/controller/MessagingController.java b/src/com/fsck/k9/controller/MessagingController.java
index d71c06997..49ecfea36 100644
--- a/src/com/fsck/k9/controller/MessagingController.java
+++ b/src/com/fsck/k9/controller/MessagingController.java
@@ -299,8 +299,8 @@ public class MessagingController implements Runnable {
          *
          * @return Message reference list
          */
-        public ArrayList<MessageReference> getAllMessageRefs() {
-            ArrayList<MessageReference> refs = new ArrayList<MessageReference>();
+        public List<MessageReference> getAllMessageRefs() {
+            List<MessageReference> refs = new ArrayList<MessageReference>();
             for (Message m : messages) {
                 refs.add(m.makeMessageReference());
             }
@@ -993,7 +993,7 @@ public class MessagingController implements Runnable {
             localFolder.open(Folder.OPEN_MODE_RW);
             localFolder.updateLastUid();
             Message[] localMessages = localFolder.getMessages(null);
-            HashMap<String, Message> localUidMap = new HashMap<String, Message>();
+            Map<String, Message> localUidMap = new HashMap<String, Message>();
             for (Message message : localMessages) {
                 localUidMap.put(message.getUid(), message);
             }
@@ -1059,8 +1059,8 @@ public class MessagingController implements Runnable {
             }
 
             Message[] remoteMessageArray = EMPTY_MESSAGE_ARRAY;
-            final ArrayList<Message> remoteMessages = new ArrayList<Message>();
-            HashMap<String, Message> remoteUidMap = new HashMap<String, Message>();
+            final List<Message> remoteMessages = new ArrayList<Message>();
+            Map<String, Message> remoteUidMap = new HashMap<String, Message>();
 
             if (K9.DEBUG)
                 Log.v(K9.LOG_TAG, "SYNC: Remote message count for folder " + folder + " is " + remoteMessageCount);
@@ -1117,7 +1117,7 @@ public class MessagingController implements Runnable {
              * Remove any messages that are in the local store but no longer on the remote store or are too old
              */
             if (account.syncRemoteDeletions()) {
-                ArrayList<Message> destroyMessages = new ArrayList<Message>();
+                List<Message> destroyMessages = new ArrayList<Message>();
                 for (Message localMessage : localMessages) {
                     if (remoteUidMap.get(localMessage.getUid()) == null) {
                         destroyMessages.add(localMessage);
@@ -1280,7 +1280,7 @@ public class MessagingController implements Runnable {
             Log.e(K9.LOG_TAG, "Unable to getUnreadMessageCount for account: " + account, e);
         }
 
-        ArrayList<Message> syncFlagMessages = new ArrayList<Message>();
+        List<Message> syncFlagMessages = new ArrayList<Message>();
         List<Message> unsyncedMessages = new ArrayList<Message>();
         final AtomicInteger newMessages = new AtomicInteger(0);
 
@@ -1300,8 +1300,8 @@ public class MessagingController implements Runnable {
             Log.d(K9.LOG_TAG, "SYNC: Have " + unsyncedMessages.size() + " unsynced messages");
 
         messages.clear();
-        final ArrayList<Message> largeMessages = new ArrayList<Message>();
-        final ArrayList<Message> smallMessages = new ArrayList<Message>();
+        final List<Message> largeMessages = new ArrayList<Message>();
+        final List<Message> smallMessages = new ArrayList<Message>();
         if (!unsyncedMessages.isEmpty()) {
 
             /*
@@ -1416,7 +1416,7 @@ public class MessagingController implements Runnable {
                                             final Folder remoteFolder,
                                             final Account account,
                                             final List<Message> unsyncedMessages,
-                                            final ArrayList<Message> syncFlagMessages,
+                                            final List<Message> syncFlagMessages,
                                             boolean flagSyncOnly) throws MessagingException {
         if (message.isSet(Flag.DELETED)) {
             syncFlagMessages.add(message);
@@ -1475,8 +1475,8 @@ public class MessagingController implements Runnable {
     private void fetchUnsyncedMessages(final Account account, final Folder remoteFolder,
                                        final LocalFolder localFolder,
                                        List<Message> unsyncedMessages,
-                                       final ArrayList<Message> smallMessages,
-                                       final ArrayList<Message> largeMessages,
+                                       final List<Message> smallMessages,
+                                       final List<Message> largeMessages,
                                        final AtomicInteger progress,
                                        final int todo,
                                        FetchProfile fp) throws MessagingException {
@@ -1611,7 +1611,7 @@ public class MessagingController implements Runnable {
 
     private void downloadSmallMessages(final Account account, final Folder remoteFolder,
                                        final LocalFolder localFolder,
-                                       ArrayList<Message> smallMessages,
+                                       List<Message> smallMessages,
                                        final AtomicInteger progress,
                                        final int unreadBeforeStart,
                                        final AtomicInteger newMessages,
@@ -1690,7 +1690,7 @@ public class MessagingController implements Runnable {
 
     private void downloadLargeMessages(final Account account, final Folder remoteFolder,
                                        final LocalFolder localFolder,
-                                       ArrayList<Message> largeMessages,
+                                       List<Message> largeMessages,
                                        final AtomicInteger progress,
                                        final int unreadBeforeStart,
                                        final AtomicInteger newMessages,
@@ -1815,7 +1815,7 @@ public class MessagingController implements Runnable {
 
     private void refreshLocalMessageFlags(final Account account, final Folder remoteFolder,
                                           final LocalFolder localFolder,
-                                          ArrayList<Message> syncFlagMessages,
+                                          List<Message> syncFlagMessages,
                                           final AtomicInteger progress,
                                           final int todo
                                          ) throws MessagingException {
@@ -1952,7 +1952,7 @@ public class MessagingController implements Runnable {
 
     private void processPendingCommandsSynchronous(Account account) throws MessagingException {
         LocalStore localStore = account.getLocalStore();
-        ArrayList<PendingCommand> commands = localStore.getPendingCommands();
+        List<PendingCommand> commands = localStore.getPendingCommands();
 
         int progress = 0;
         int todo = commands.size();
@@ -4863,7 +4863,7 @@ public class MessagingController implements Runnable {
 
         String accountDescr = (account.getDescription() != null) ?
                 account.getDescription() : account.getEmail();
-        final ArrayList<MessageReference> allRefs = data.getAllMessageRefs();
+        final List<MessageReference> allRefs = data.getAllMessageRefs();
 
         if (platformSupportsExtendedNotifications() && !privacyModeEnabled) {
             if (newMessages > 1) {
@@ -5424,7 +5424,7 @@ public class MessagingController implements Runnable {
         return taccount.getDescription() + ":" + tfolderName;
     }
     static class MemorizingListener extends MessagingListener {
-        HashMap<String, Memory> memories = new HashMap<String, Memory>(31);
+        Map<String, Memory> memories = new HashMap<String, Memory>(31);
 
         Memory getMemory(Account account, String folderName) {
             Memory memory = memories.get(getMemoryKey(account, folderName));
diff --git a/src/com/fsck/k9/fragment/MessageListFragment.java b/src/com/fsck/k9/fragment/MessageListFragment.java
index e72da130d..b73bfa495 100644
--- a/src/com/fsck/k9/fragment/MessageListFragment.java
+++ b/src/com/fsck/k9/fragment/MessageListFragment.java
@@ -2995,8 +2995,8 @@ public class MessageListFragment extends Fragment implements OnItemClickListener
         super.onStop();
     }
 
-    public ArrayList<MessageReference> getMessageReferences() {
-        ArrayList<MessageReference> messageRefs = new ArrayList<MessageReference>();
+    public List<MessageReference> getMessageReferences() {
+        List<MessageReference> messageRefs = new ArrayList<MessageReference>();
 
         for (int i = 0, len = mAdapter.getCount(); i < len; i++) {
             Cursor cursor = (Cursor) mAdapter.getItem(i);
diff --git a/src/com/fsck/k9/helper/Contacts.java b/src/com/fsck/k9/helper/Contacts.java
index 56866c21c..75c084aba 100644
--- a/src/com/fsck/k9/helper/Contacts.java
+++ b/src/com/fsck/k9/helper/Contacts.java
@@ -13,6 +13,7 @@ import com.fsck.k9.K9;
 import com.fsck.k9.mail.Address;
 
 import java.util.ArrayList;
+import java.util.List;
 
 /**
  * Helper class to access the contacts stored on the device.
@@ -276,7 +277,7 @@ public class Contacts {
      */
     public ContactItem extractInfoFromContactPickerIntent(final Intent intent) {
         Cursor cursor = null;
-        ArrayList<String> email = new ArrayList<String>();
+        List<String> email = new ArrayList<String>();
 
         try {
             Uri result = intent.getData();
diff --git a/src/com/fsck/k9/helper/Utility.java b/src/com/fsck/k9/helper/Utility.java
index ae8d9bb71..c450ad448 100644
--- a/src/com/fsck/k9/helper/Utility.java
+++ b/src/com/fsck/k9/helper/Utility.java
@@ -20,10 +20,13 @@ import com.fsck.k9.mail.filter.Base64;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
+import java.io.Serializable;
 import java.nio.charset.Charset;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Locale;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -704,4 +707,23 @@ public class Utility {
         }
         return sMainThreadHandler;
     }
+
+    public static <T> Serializable toSerializableList(List<T> list) {
+        return list instanceof Serializable ?
+                (Serializable) list :
+                new ArrayList<T>(list);
+    }
+
+    public static <T> ArrayList<T> toArrayList(List<T> list) {
+        return list instanceof ArrayList ?
+                (ArrayList<T>) list :
+                new ArrayList<T>(list);
+    }
+
+
+    public static <T,U> Serializable toSerializableConcurrentMap(ConcurrentMap<T,U> list) {
+        return list instanceof ConcurrentHashMap ?
+                (ConcurrentHashMap<T,U>) list :
+                new ConcurrentHashMap<T,U>(list);
+    }
 }
diff --git a/src/com/fsck/k9/mail/Address.java b/src/com/fsck/k9/mail/Address.java
index b5bdcc854..ef79b3790 100644
--- a/src/com/fsck/k9/mail/Address.java
+++ b/src/com/fsck/k9/mail/Address.java
@@ -315,7 +315,7 @@ public class Address {
         if (addressList == null) {
             return new Address[] { };
         }
-        ArrayList<Address> addresses = new ArrayList<Address>();
+        List<Address> addresses = new ArrayList<Address>();
         int length = addressList.length();
         int pairStartIndex = 0;
         int pairEndIndex = 0;
diff --git a/src/com/fsck/k9/mail/Multipart.java b/src/com/fsck/k9/mail/Multipart.java
index 88651485a..567b0902d 100644
--- a/src/com/fsck/k9/mail/Multipart.java
+++ b/src/com/fsck/k9/mail/Multipart.java
@@ -13,7 +13,7 @@ import com.fsck.k9.mail.internet.TextBody;
 public abstract class Multipart implements CompositeBody {
     private Part mParent;
 
-    private final ArrayList<BodyPart> mParts = new ArrayList<BodyPart>();
+    private final List<BodyPart> mParts = new ArrayList<BodyPart>();
 
     private String mContentType;
 
diff --git a/src/com/fsck/k9/mail/Store.java b/src/com/fsck/k9/mail/Store.java
index 659b81161..5be7d7011 100644
--- a/src/com/fsck/k9/mail/Store.java
+++ b/src/com/fsck/k9/mail/Store.java
@@ -3,7 +3,9 @@ package com.fsck.k9.mail;
 
 import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
 
 import android.app.Application;
 import android.content.Context;
@@ -33,19 +35,19 @@ public abstract class Store {
     /**
      * Remote stores indexed by Uri.
      */
-    private static HashMap<String, Store> sStores = new HashMap<String, Store>();
+    private static Map<String, Store> sStores = new HashMap<String, Store>();
 
     /**
      * Local stores indexed by UUID because the Uri may change due to migration to/from SD-card.
      */
-    private static ConcurrentHashMap<String, Store> sLocalStores = new ConcurrentHashMap<String, Store>();
+    private static ConcurrentMap<String, Store> sLocalStores = new ConcurrentHashMap<String, Store>();
 
     /**
      * Lock objects indexed by account UUID.
      *
      * @see #getLocalInstance(Account, Application)
      */
-    private static ConcurrentHashMap<String, Object> sAccountLocks = new ConcurrentHashMap<String, Object>();
+    private static ConcurrentMap<String, Object> sAccountLocks = new ConcurrentHashMap<String, Object>();
 
     /**
      * Get an instance of a remote mail store.
diff --git a/src/com/fsck/k9/mail/internet/MimeHeader.java b/src/com/fsck/k9/mail/internet/MimeHeader.java
index dd6445755..12bd5fd31 100644
--- a/src/com/fsck/k9/mail/internet/MimeHeader.java
+++ b/src/com/fsck/k9/mail/internet/MimeHeader.java
@@ -36,7 +36,7 @@ public class MimeHeader {
         HEADER_ANDROID_ATTACHMENT_STORE_DATA
     };
 
-    private ArrayList<Field> mFields = new ArrayList<Field>();
+    private List<Field> mFields = new ArrayList<Field>();
     private String mCharset = null;
 
     public void clear() {
@@ -72,7 +72,7 @@ public class MimeHeader {
     }
 
     public String[] getHeader(String name) {
-        ArrayList<String> values = new ArrayList<String>();
+        List<String> values = new ArrayList<String>();
         for (Field field : mFields) {
             if (field.name.equalsIgnoreCase(name)) {
                 values.add(field.value);
@@ -85,7 +85,7 @@ public class MimeHeader {
     }
 
     public void removeHeader(String name) {
-        ArrayList<Field> removeFields = new ArrayList<Field>();
+        List<Field> removeFields = new ArrayList<Field>();
         for (Field field : mFields) {
             if (field.name.equalsIgnoreCase(name)) {
                 removeFields.add(field);
diff --git a/src/com/fsck/k9/mail/store/ImapStore.java b/src/com/fsck/k9/mail/store/ImapStore.java
index f66215e0b..1987e0b5a 100644
--- a/src/com/fsck/k9/mail/store/ImapStore.java
+++ b/src/com/fsck/k9/mail/store/ImapStore.java
@@ -1356,9 +1356,9 @@ public class ImapStore extends Store {
         private List<Message> search(ImapSearcher searcher, MessageRetrievalListener listener) throws MessagingException {
 
             checkOpen(); //only need READ access
-            ArrayList<Message> messages = new ArrayList<Message>();
+            List<Message> messages = new ArrayList<Message>();
             try {
-                ArrayList<Long> uids = new ArrayList<Long>();
+                List<Long> uids = new ArrayList<Long>();
                 List<ImapResponse> responses = searcher.search(); //
                 for (ImapResponse response : responses) {
                     if (response.mTag == null) {
@@ -1403,11 +1403,11 @@ public class ImapStore extends Store {
         public Message[] getMessages(String[] uids, MessageRetrievalListener listener)
         throws MessagingException {
             checkOpen(); //only need READ access
-            ArrayList<Message> messages = new ArrayList<Message>();
+            List<Message> messages = new ArrayList<Message>();
             try {
                 if (uids == null) {
                     List<ImapResponse> responses = executeSimpleCommand("UID SEARCH 1:* NOT DELETED");
-                    ArrayList<String> tempUids = new ArrayList<String>();
+                    List<String> tempUids = new ArrayList<String>();
                     for (ImapResponse response : responses) {
                         if (ImapResponseParser.equalsIgnoreCase(response.get(0), "SEARCH")) {
                             for (int i = 1, count = response.size(); i < count; i++) {
@@ -1441,7 +1441,7 @@ public class ImapStore extends Store {
             }
             checkOpen(); //only need READ access
             List<String> uids = new ArrayList<String>(messages.length);
-            HashMap<String, Message> messageMap = new HashMap<String, Message>();
+            Map<String, Message> messageMap = new HashMap<String, Message>();
             for (Message msg : messages) {
                 String uid = msg.getUid();
                 uids.add(uid);
@@ -2089,7 +2089,7 @@ public class ImapStore extends Store {
         }
 
         private String combineFlags(Flag[] flags) {
-            ArrayList<String> flagNames = new ArrayList<String>();
+            List<String> flagNames = new ArrayList<String>();
             for (Flag flag : flags) {
                 if (flag == Flag.SEEN) {
                     flagNames.add("\\Seen");
@@ -2733,10 +2733,10 @@ public class ImapStore extends Store {
             return response;
         }
 
-        protected ArrayList<ImapResponse> readStatusResponse(String tag,
+        protected List<ImapResponse> readStatusResponse(String tag,
                 String commandToLog, UntaggedHandler untaggedHandler)
                 throws IOException, MessagingException {
-            ArrayList<ImapResponse> responses = new ArrayList<ImapResponse>();
+            List<ImapResponse> responses = new ArrayList<ImapResponse>();
             ImapResponse response;
             do {
                 response = mParser.readResponse();
@@ -3552,9 +3552,9 @@ public class ImapStore extends Store {
     }
 
     private static class FetchBodyCallback implements ImapResponseParser.IImapResponseCallback {
-        private HashMap<String, Message> mMessageMap;
+        private Map<String, Message> mMessageMap;
 
-        FetchBodyCallback(HashMap<String, Message> mesageMap) {
+        FetchBodyCallback(Map<String, Message> mesageMap) {
             mMessageMap = mesageMap;
         }
 
diff --git a/src/com/fsck/k9/mail/store/Pop3Store.java b/src/com/fsck/k9/mail/store/Pop3Store.java
index fa2c7049c..414b334b2 100644
--- a/src/com/fsck/k9/mail/store/Pop3Store.java
+++ b/src/com/fsck/k9/mail/store/Pop3Store.java
@@ -196,7 +196,7 @@ public class Pop3Store extends Store {
     private String mClientCertificateAlias;
     private AuthType mAuthType;
     private ConnectionSecurity mConnectionSecurity;
-    private HashMap<String, Folder> mFolders = new HashMap<String, Folder>();
+    private Map<String, Folder> mFolders = new HashMap<String, Folder>();
     private Pop3Capabilities mCapabilities;
 
     /**
@@ -274,9 +274,9 @@ public class Pop3Store extends Store {
         private Socket mSocket;
         private InputStream mIn;
         private OutputStream mOut;
-        private HashMap<String, Pop3Message> mUidToMsgMap = new HashMap<String, Pop3Message>();
-        private HashMap<Integer, Pop3Message> mMsgNumToMsgMap = new HashMap<Integer, Pop3Message>();
-        private HashMap<String, Integer> mUidToMsgNumMap = new HashMap<String, Integer>();
+        private Map<String, Pop3Message> mUidToMsgMap = new HashMap<String, Pop3Message>();
+        private Map<Integer, Pop3Message> mMsgNumToMsgMap = new HashMap<Integer, Pop3Message>();
+        private Map<String, Integer> mUidToMsgNumMap = new HashMap<String, Integer>();
         private String mName;
         private int mMessageCount;
 
@@ -577,7 +577,7 @@ public class Pop3Store extends Store {
             } catch (IOException ioe) {
                 throw new MessagingException("getMessages", ioe);
             }
-            ArrayList<Message> messages = new ArrayList<Message>();
+            List<Message> messages = new ArrayList<Message>();
             int i = 0;
             for (int msgNum = start; msgNum <= end; msgNum++) {
                 Pop3Message message = mMsgNumToMsgMap.get(msgNum);
@@ -686,7 +686,7 @@ public class Pop3Store extends Store {
             }
         }
 
-        private void indexUids(ArrayList<String> uids)
+        private void indexUids(List<String> uids)
         throws MessagingException, IOException {
             Set<String> unindexedUids = new HashSet<String>();
             for (String uid : uids) {
@@ -764,7 +764,7 @@ public class Pop3Store extends Store {
             if (messages == null || messages.length == 0) {
                 return;
             }
-            ArrayList<String> uids = new ArrayList<String>();
+            List<String> uids = new ArrayList<String>();
             for (Message message : messages) {
                 uids.add(message.getUid());
             }
@@ -988,7 +988,7 @@ public class Pop3Store extends Store {
                  */
                 return;
             }
-            ArrayList<String> uids = new ArrayList<String>();
+            List<String> uids = new ArrayList<String>();
             try {
                 for (Message message : messages) {
                     uids.add(message.getUid());
diff --git a/src/com/fsck/k9/mail/store/WebDavStore.java b/src/com/fsck/k9/mail/store/WebDavStore.java
index 1148927bb..650be8812 100644
--- a/src/com/fsck/k9/mail/store/WebDavStore.java
+++ b/src/com/fsck/k9/mail/store/WebDavStore.java
@@ -293,7 +293,7 @@ public class WebDavStore extends Store {
     private String mCachedLoginUrl;
 
     private Folder mSendFolder = null;
-    private HashMap<String, WebDavFolder> mFolderList = new HashMap<String, WebDavFolder>();
+    private Map<String, WebDavFolder> mFolderList = new HashMap<String, WebDavFolder>();
 
 
     public WebDavStore(Account account) throws MessagingException {
@@ -363,7 +363,7 @@ public class WebDavStore extends Store {
 
     @Override
     public List <? extends Folder > getPersonalNamespaces(boolean forceListAll) throws MessagingException {
-        LinkedList<Folder> folderList = new LinkedList<Folder>();
+        List<Folder> folderList = new LinkedList<Folder>();
         /**
          * We have to check authentication here so we have the proper URL stored
          */
@@ -373,13 +373,13 @@ public class WebDavStore extends Store {
          *  Firstly we get the "special" folders list (inbox, outbox, etc)
          *  and setup the account accordingly
          */
-        HashMap<String, String> headers = new HashMap<String, String>();
+        Map<String, String> headers = new HashMap<String, String>();
         DataSet dataset = new DataSet();
         headers.put("Depth", "0");
         headers.put("Brief", "t");
         dataset = processRequest(this.mUrl, "PROPFIND", getSpecialFoldersList(), headers);
 
-        HashMap<String, String> specialFoldersMap = dataset.getSpecialFolderToUrl();
+        Map<String, String> specialFoldersMap = dataset.getSpecialFolderToUrl();
         String folderName = getFolderName(specialFoldersMap.get(DAV_MAIL_INBOX_FOLDER));
         if (folderName != null) {
             mAccount.setAutoExpandFolderName(folderName);
@@ -825,7 +825,7 @@ public class WebDavStore extends Store {
         request.setMethod("POST");
 
         // Build the POST data.
-        ArrayList<BasicNameValuePair> pairs = new ArrayList<BasicNameValuePair>();
+        List<BasicNameValuePair> pairs = new ArrayList<BasicNameValuePair>();
         pairs.add(new BasicNameValuePair("destination", mUrl));
         pairs.add(new BasicNameValuePair("username", mUsername));
         pairs.add(new BasicNameValuePair("password", mPassword));
@@ -1037,7 +1037,7 @@ public class WebDavStore extends Store {
     }
 
     private InputStream sendRequest(String url, String method, StringEntity messageBody,
-                                    HashMap<String, String> headers, boolean tryAuth)
+                                    Map<String, String> headers, boolean tryAuth)
     throws MessagingException {
         InputStream istream = null;
 
@@ -1115,12 +1115,12 @@ public class WebDavStore extends Store {
      * not all requests will need them. There are two signatures to support calls that don't require parsing of the
      * response.
      */
-    private DataSet processRequest(String url, String method, String messageBody, HashMap<String, String> headers)
+    private DataSet processRequest(String url, String method, String messageBody, Map<String, String> headers)
     throws MessagingException {
         return processRequest(url, method, messageBody, headers, true);
     }
 
-    private DataSet processRequest(String url, String method, String messageBody, HashMap<String, String> headers,
+    private DataSet processRequest(String url, String method, String messageBody, Map<String, String> headers,
                                    boolean needsParsing)
     throws MessagingException {
         DataSet dataset = new DataSet();
@@ -1294,8 +1294,8 @@ public class WebDavStore extends Store {
                 uids[i] = messages[i].getUid();
             }
             String messageBody = "";
-            HashMap<String, String> headers = new HashMap<String, String>();
-            HashMap<String, String> uidToUrl = getMessageUrls(uids);
+            Map<String, String> headers = new HashMap<String, String>();
+            Map<String, String> uidToUrl = getMessageUrls(uids);
             String[] urls = new String[uids.length];
 
             for (int i = 0, count = uids.length; i < count; i++) {
@@ -1320,7 +1320,7 @@ public class WebDavStore extends Store {
         private int getMessageCount(boolean read) throws MessagingException {
             String isRead;
             int messageCount = 0;
-            HashMap<String, String> headers = new HashMap<String, String>();
+            Map<String, String> headers = new HashMap<String, String>();
             String messageBody;
 
             if (read) {
@@ -1406,9 +1406,9 @@ public class WebDavStore extends Store {
         @Override
         public Message[] getMessages(int start, int end, Date earliestDate, MessageRetrievalListener listener)
         throws MessagingException {
-            ArrayList<Message> messages = new ArrayList<Message>();
+            List<Message> messages = new ArrayList<Message>();
             String[] uids;
-            HashMap<String, String> headers = new HashMap<String, String>();
+            Map<String, String> headers = new HashMap<String, String>();
             int uidsLength = -1;
 
             String messageBody;
@@ -1434,7 +1434,7 @@ public class WebDavStore extends Store {
             DataSet dataset = processRequest(this.mFolderUrl, "SEARCH", messageBody, headers);
 
             uids = dataset.getUids();
-            HashMap<String, String> uidToUrl = dataset.getUidToUrl();
+            Map<String, String> uidToUrl = dataset.getUidToUrl();
             uidsLength = uids.length;
 
             for (int i = 0; i < uidsLength; i++) {
@@ -1460,7 +1460,7 @@ public class WebDavStore extends Store {
 
         @Override
         public Message[] getMessages(String[] uids, MessageRetrievalListener listener) throws MessagingException {
-            ArrayList<Message> messageList = new ArrayList<Message>();
+            List<Message> messageList = new ArrayList<Message>();
             Message[] messages;
 
             if (uids == null ||
@@ -1485,8 +1485,8 @@ public class WebDavStore extends Store {
             return messages;
         }
 
-        private HashMap<String, String> getMessageUrls(String[] uids) throws MessagingException {
-            HashMap<String, String> headers = new HashMap<String, String>();
+        private Map<String, String> getMessageUrls(String[] uids) throws MessagingException {
+            Map<String, String> headers = new HashMap<String, String>();
             String messageBody;
 
             /** Retrieve and parse the XML entity for our messages */
@@ -1494,7 +1494,7 @@ public class WebDavStore extends Store {
             headers.put("Brief", "t");
 
             DataSet dataset = processRequest(this.mFolderUrl, "SEARCH", messageBody, headers);
-            HashMap<String, String> uidToUrl = dataset.getUidToUrl();
+            Map<String, String> uidToUrl = dataset.getUidToUrl();
 
             return uidToUrl;
         }
@@ -1650,7 +1650,7 @@ public class WebDavStore extends Store {
          * we do a series of medium calls instead of one large massive call or a large number of smaller calls.
          */
         private void fetchFlags(Message[] startMessages, MessageRetrievalListener listener) throws MessagingException {
-            HashMap<String, String> headers = new HashMap<String, String>();
+            Map<String, String> headers = new HashMap<String, String>();
             String messageBody = "";
             Message[] messages = new Message[20];
             String[] uids;
@@ -1689,7 +1689,7 @@ public class WebDavStore extends Store {
                 throw new MessagingException("Data Set from request was null");
             }
 
-            HashMap<String, Boolean> uidToReadStatus = dataset.getUidToRead();
+            Map<String, Boolean> uidToReadStatus = dataset.getUidToRead();
 
             for (int i = 0, count = messages.length; i < count; i++) {
                 if (!(messages[i] instanceof WebDavMessage)) {
@@ -1720,7 +1720,7 @@ public class WebDavStore extends Store {
          */
         private void fetchEnvelope(Message[] startMessages, MessageRetrievalListener listener)
         throws MessagingException {
-            HashMap<String, String> headers = new HashMap<String, String>();
+            Map<String, String> headers = new HashMap<String, String>();
             String messageBody = "";
             String[] uids;
             Message[] messages = new Message[10];
@@ -1802,8 +1802,8 @@ public class WebDavStore extends Store {
 
         private void markServerMessagesRead(String[] uids, boolean read) throws MessagingException {
             String messageBody = "";
-            HashMap<String, String> headers = new HashMap<String, String>();
-            HashMap<String, String> uidToUrl = getMessageUrls(uids);
+            Map<String, String> headers = new HashMap<String, String>();
+            Map<String, String> uidToUrl = getMessageUrls(uids);
             String[] urls = new String[uids.length];
 
             for (int i = 0, count = uids.length; i < count; i++) {
@@ -1818,10 +1818,10 @@ public class WebDavStore extends Store {
         }
 
         private void deleteServerMessages(String[] uids) throws MessagingException {
-            HashMap<String, String> uidToUrl = getMessageUrls(uids);
+            Map<String, String> uidToUrl = getMessageUrls(uids);
 
             for (String uid : uids) {
-                HashMap<String, String> headers = new HashMap<String, String>();
+                Map<String, String> headers = new HashMap<String, String>();
                 String url = uidToUrl.get(uid);
                 String destinationUrl = generateDeleteUrl(url);
 
@@ -2005,7 +2005,7 @@ public class WebDavStore extends Store {
 
         public void setNewHeaders(ParsedMessageEnvelope envelope) throws MessagingException {
             String[] headers = envelope.getHeaderList();
-            HashMap<String, String> messageHeaders = envelope.getMessageHeaders();
+            Map<String, String> messageHeaders = envelope.getMessageHeaders();
 
             for (String header : headers) {
                 String headerValue = messageHeaders.get(header);
@@ -2107,8 +2107,8 @@ public class WebDavStore extends Store {
 
         private boolean mReadStatus = false;
         private String mUid = "";
-        private HashMap<String, String> mMessageHeaders = new HashMap<String, String>();
-        private ArrayList<String> mHeaders = new ArrayList<String>();
+        private Map<String, String> mMessageHeaders = new HashMap<String, String>();
+        private List<String> mHeaders = new ArrayList<String>();
 
         public void addHeader(String field, String value) {
             String headerName = HEADER_MAPPINGS.get(field);
@@ -2119,7 +2119,7 @@ public class WebDavStore extends Store {
             }
         }
 
-        public HashMap<String, String> getMessageHeaders() {
+        public Map<String, String> getMessageHeaders() {
             return this.mMessageHeaders;
         }
 
@@ -2151,9 +2151,9 @@ public class WebDavStore extends Store {
      * depending on the accessor calls made.
      */
     public class DataSet {
-        private HashMap<String, HashMap<String, String>> mData = new HashMap<String, HashMap<String, String>>();
+        private Map<String, Map<String, String>> mData = new HashMap<String, Map<String, String>>();
         private StringBuilder mUid = new StringBuilder();
-        private HashMap<String, String> mTempData = new HashMap<String, String>();
+        private Map<String, String> mTempData = new HashMap<String, String>();
 
         public void addValue(String value, String tagName) {
             if (tagName.equals("uid")) {
@@ -2185,9 +2185,9 @@ public class WebDavStore extends Store {
         /**
          * Returns a hashmap of special folder name => special folder url
          */
-        public HashMap<String, String> getSpecialFolderToUrl() {
+        public Map<String, String> getSpecialFolderToUrl() {
             // We return the first (and only) map
-            for (HashMap<String, String> folderMap : mData.values()) {
+            for (Map<String, String> folderMap : mData.values()) {
                 return folderMap;
             }
             return new HashMap<String, String>();
@@ -2196,11 +2196,11 @@ public class WebDavStore extends Store {
         /**
          * Returns a hashmap of Message UID => Message Url
          */
-        public HashMap<String, String> getUidToUrl() {
-            HashMap<String, String> uidToUrl = new HashMap<String, String>();
+        public Map<String, String> getUidToUrl() {
+            Map<String, String> uidToUrl = new HashMap<String, String>();
 
             for (String uid : mData.keySet()) {
-                HashMap<String, String> data = mData.get(uid);
+                Map<String, String> data = mData.get(uid);
                 String value = data.get("href");
                 if (value != null &&
                         !value.equals("")) {
@@ -2214,11 +2214,11 @@ public class WebDavStore extends Store {
         /**
          * Returns a hashmap of Message UID => Read Status
          */
-        public HashMap<String, Boolean> getUidToRead() {
-            HashMap<String, Boolean> uidToRead = new HashMap<String, Boolean>();
+        public Map<String, Boolean> getUidToRead() {
+            Map<String, Boolean> uidToRead = new HashMap<String, Boolean>();
 
             for (String uid : mData.keySet()) {
-                HashMap<String, String> data = mData.get(uid);
+                Map<String, String> data = mData.get(uid);
                 String readStatus = data.get("read");
                 if (readStatus != null && !readStatus.equals("")) {
                     Boolean value = !readStatus.equals("0");
@@ -2238,10 +2238,10 @@ public class WebDavStore extends Store {
          * Returns an array of all hrefs (urls) that were received
          */
         public String[] getHrefs() {
-            ArrayList<String> hrefs = new ArrayList<String>();
+            List<String> hrefs = new ArrayList<String>();
 
             for (String uid : mData.keySet()) {
-                HashMap<String, String> data = mData.get(uid);
+                Map<String, String> data = mData.get(uid);
                 String href = data.get("href");
                 hrefs.add(href);
             }
@@ -2253,7 +2253,7 @@ public class WebDavStore extends Store {
          * Return an array of all Message UIDs that were received
          */
         public String[] getUids() {
-            ArrayList<String> uids = new ArrayList<String>();
+            List<String> uids = new ArrayList<String>();
 
             for (String uid : mData.keySet()) {
                 uids.add(uid);
@@ -2274,7 +2274,7 @@ public class WebDavStore extends Store {
             int messageCount = 0;
 
             for (String uid : mData.keySet()) {
-                HashMap<String, String> data = mData.get(uid);
+                Map<String, String> data = mData.get(uid);
                 String count = data.get("visiblecount");
 
                 if (count != null &&
@@ -2288,14 +2288,14 @@ public class WebDavStore extends Store {
         }
 
         /**
-         * Returns a HashMap of message UID => ParsedMessageEnvelope
+         * Returns a Map of message UID => ParsedMessageEnvelope
          */
-        public HashMap<String, ParsedMessageEnvelope> getMessageEnvelopes() {
-            HashMap<String, ParsedMessageEnvelope> envelopes = new HashMap<String, ParsedMessageEnvelope>();
+        public Map<String, ParsedMessageEnvelope> getMessageEnvelopes() {
+            Map<String, ParsedMessageEnvelope> envelopes = new HashMap<String, ParsedMessageEnvelope>();
 
             for (String uid : mData.keySet()) {
                 ParsedMessageEnvelope envelope = new ParsedMessageEnvelope();
-                HashMap<String, String> data = mData.get(uid);
+                Map<String, String> data = mData.get(uid);
 
                 if (data != null) {
                     for (Map.Entry<String, String> entry : data.entrySet()) {
diff --git a/src/com/fsck/k9/mail/store/imap/ImapUtility.java b/src/com/fsck/k9/mail/store/imap/ImapUtility.java
index b7312eae7..51d1aa070 100644
--- a/src/com/fsck/k9/mail/store/imap/ImapUtility.java
+++ b/src/com/fsck/k9/mail/store/imap/ImapUtility.java
@@ -48,7 +48,7 @@ public class ImapUtility {
      *         list is returned.
      */
     public static List<String> getImapSequenceValues(String set) {
-        ArrayList<String> list = new ArrayList<String>();
+        List<String> list = new ArrayList<String>();
         if (set != null) {
             String[] setItems = set.split(",");
             for (String item : setItems) {
@@ -83,7 +83,7 @@ public class ImapUtility {
      *         is returned.
      */
     public static List<String> getImapRangeValues(String range) {
-        ArrayList<String> list = new ArrayList<String>();
+        List<String> list = new ArrayList<String>();
         try {
             if (range != null) {
                 int colonPos = range.indexOf(':');
diff --git a/src/com/fsck/k9/mail/store/local/LocalFolder.java b/src/com/fsck/k9/mail/store/local/LocalFolder.java
index 009d630ae..627c4977c 100644
--- a/src/com/fsck/k9/mail/store/local/LocalFolder.java
+++ b/src/com/fsck/k9/mail/store/local/LocalFolder.java
@@ -971,7 +971,7 @@ public class LocalFolder extends Folder implements Serializable {
         if (uids == null) {
             return getMessages(listener);
         }
-        ArrayList<Message> messages = new ArrayList<Message>();
+        List<Message> messages = new ArrayList<Message>();
         for (String uid : uids) {
             Message message = getMessage(uid);
             if (message != null) {
diff --git a/src/com/fsck/k9/mail/store/local/LocalMessage.java b/src/com/fsck/k9/mail/store/local/LocalMessage.java
index f7630a364..474a4c849 100644
--- a/src/com/fsck/k9/mail/store/local/LocalMessage.java
+++ b/src/com/fsck/k9/mail/store/local/LocalMessage.java
@@ -4,6 +4,7 @@ import java.io.IOException;
 import java.io.OutputStream;
 import java.util.ArrayList;
 import java.util.Date;
+import java.util.List;
 import java.util.Set;
 
 import android.content.ContentValues;
@@ -492,7 +493,7 @@ public class LocalMessage extends MimeMessage {
     }
 
     private void loadHeaders() throws UnavailableStorageException {
-        ArrayList<LocalMessage> messages = new ArrayList<LocalMessage>();
+        List<LocalMessage> messages = new ArrayList<LocalMessage>();
         messages.add(this);
         mHeadersLoaded = true; // set true before calling populate headers to stop recursion
         ((LocalFolder) mFolder).populateHeaders(messages);
diff --git a/src/com/fsck/k9/mail/store/local/LocalStore.java b/src/com/fsck/k9/mail/store/local/LocalStore.java
index 17b9fac68..92525d708 100644
--- a/src/com/fsck/k9/mail/store/local/LocalStore.java
+++ b/src/com/fsck/k9/mail/store/local/LocalStore.java
@@ -425,10 +425,10 @@ public class LocalStore extends Store implements Serializable {
         });
     }
 
-    public ArrayList<PendingCommand> getPendingCommands() throws UnavailableStorageException {
-        return database.execute(false, new DbCallback<ArrayList<PendingCommand>>() {
+    public List<PendingCommand> getPendingCommands() throws UnavailableStorageException {
+        return database.execute(false, new DbCallback<List<PendingCommand>>() {
             @Override
-            public ArrayList<PendingCommand> doDbWork(final SQLiteDatabase db) throws WrappedException {
+            public List<PendingCommand> doDbWork(final SQLiteDatabase db) throws WrappedException {
                 Cursor cursor = null;
                 try {
                     cursor = db.query("pending_commands",
@@ -438,7 +438,7 @@ public class LocalStore extends Store implements Serializable {
                                       null,
                                       null,
                                       "id ASC");
-                    ArrayList<PendingCommand> commands = new ArrayList<PendingCommand>();
+                    List<PendingCommand> commands = new ArrayList<PendingCommand>();
                     while (cursor.moveToNext()) {
                         PendingCommand command = new PendingCommand();
                         command.mId = cursor.getLong(0);
@@ -559,7 +559,7 @@ public class LocalStore extends Store implements Serializable {
         final LocalFolder folder,
         final String queryString, final String[] placeHolders
     ) throws MessagingException {
-        final ArrayList<LocalMessage> messages = new ArrayList<LocalMessage>();
+        final List<LocalMessage> messages = new ArrayList<LocalMessage>();
         final int j = database.execute(false, new DbCallback<Integer>() {
             @Override
             public Integer doDbWork(final SQLiteDatabase db) throws WrappedException {
diff --git a/src/com/fsck/k9/mail/transport/SmtpTransport.java b/src/com/fsck/k9/mail/transport/SmtpTransport.java
index bd50419f1..428c0dce2 100644
--- a/src/com/fsck/k9/mail/transport/SmtpTransport.java
+++ b/src/com/fsck/k9/mail/transport/SmtpTransport.java
@@ -256,7 +256,7 @@ public class SmtpTransport extends Transport {
                 }
             }
 
-            HashMap<String,String> extensions = sendHello(localHost);
+            Map<String,String> extensions = sendHello(localHost);
 
             m8bitEncodingAllowed = extensions.containsKey("8BITMIME");
 
@@ -419,7 +419,7 @@ public class SmtpTransport extends Transport {
      * @param host
      *         The EHLO/HELO parameter as defined by the RFC.
      *
-     * @return A (possibly empty) {@code HashMap<String,String>} of extensions (upper case) and
+     * @return A (possibly empty) {@code Map<String,String>} of extensions (upper case) and
      * their parameters (possibly 0 length) as returned by the EHLO command
      *
      * @throws IOException
@@ -427,8 +427,8 @@ public class SmtpTransport extends Transport {
      * @throws MessagingException
      *          In case of a malformed response.
      */
-    private HashMap<String,String> sendHello(String host) throws IOException, MessagingException {
-        HashMap<String, String> extensions = new HashMap<String, String>();
+    private Map<String,String> sendHello(String host) throws IOException, MessagingException {
+        Map<String, String> extensions = new HashMap<String, String>();
         try {
             List<String> results = executeSimpleCommand("EHLO " + host);
             // Remove the EHLO greeting response
@@ -453,7 +453,7 @@ public class SmtpTransport extends Transport {
 
     @Override
     public void sendMessage(Message message) throws MessagingException {
-        ArrayList<Address> addresses = new ArrayList<Address>();
+        List<Address> addresses = new ArrayList<Address>();
         {
             addresses.addAll(Arrays.asList(message.getRecipients(RecipientType.TO)));
             addresses.addAll(Arrays.asList(message.getRecipients(RecipientType.CC)));
@@ -461,12 +461,12 @@ public class SmtpTransport extends Transport {
         }
         message.setRecipients(RecipientType.BCC, null);
 
-        HashMap<String, ArrayList<String>> charsetAddressesMap =
-            new HashMap<String, ArrayList<String>>();
+        Map<String, List<String>> charsetAddressesMap =
+            new HashMap<String, List<String>>();
         for (Address address : addresses) {
             String addressString = address.getAddress();
             String charset = MimeUtility.getCharsetFromAddress(addressString);
-            ArrayList<String> addressesOfCharset = charsetAddressesMap.get(charset);
+            List<String> addressesOfCharset = charsetAddressesMap.get(charset);
             if (addressesOfCharset == null) {
                 addressesOfCharset = new ArrayList<String>();
                 charsetAddressesMap.put(charset, addressesOfCharset);
@@ -474,16 +474,16 @@ public class SmtpTransport extends Transport {
             addressesOfCharset.add(addressString);
         }
 
-        for (Map.Entry<String, ArrayList<String>> charsetAddressesMapEntry :
+        for (Map.Entry<String, List<String>> charsetAddressesMapEntry :
                 charsetAddressesMap.entrySet()) {
             String charset = charsetAddressesMapEntry.getKey();
-            ArrayList<String> addressesOfCharset = charsetAddressesMapEntry.getValue();
+            List<String> addressesOfCharset = charsetAddressesMapEntry.getValue();
             message.setCharset(charset);
             sendMessageTo(addressesOfCharset, message);
         }
     }
 
-    private void sendMessageTo(ArrayList<String> addresses, Message message)
+    private void sendMessageTo(List<String> addresses, Message message)
     throws MessagingException {
         boolean possibleSend = false;
 
diff --git a/src/com/fsck/k9/preferences/Editor.java b/src/com/fsck/k9/preferences/Editor.java
index 88479d0e2..fdbc5d3eb 100644
--- a/src/com/fsck/k9/preferences/Editor.java
+++ b/src/com/fsck/k9/preferences/Editor.java
@@ -5,14 +5,15 @@ import com.fsck.k9.K9;
 
 import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
 import java.util.Set;
 
 public class Editor implements android.content.SharedPreferences.Editor {
     private Storage storage;
-    private HashMap<String, String> changes = new HashMap<String, String>();
-    private ArrayList<String> removals = new ArrayList<String>();
+    private Map<String, String> changes = new HashMap<String, String>();
+    private List<String> removals = new ArrayList<String>();
     private boolean removeAll = false;
 
     Map<String, String> snapshot = new HashMap<String, String>();
diff --git a/src/com/fsck/k9/preferences/Storage.java b/src/com/fsck/k9/preferences/Storage.java
index e88a9b6c3..f4c4c4d0e 100644
--- a/src/com/fsck/k9/preferences/Storage.java
+++ b/src/com/fsck/k9/preferences/Storage.java
@@ -15,16 +15,18 @@ import com.fsck.k9.helper.Utility;
 import java.net.URI;
 import java.net.URLEncoder;
 import java.util.ArrayList;
+import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
 import java.util.concurrent.CopyOnWriteArrayList;
 
 public class Storage implements SharedPreferences {
-    private static ConcurrentHashMap<Context, Storage> storages =
+    private static ConcurrentMap<Context, Storage> storages =
         new ConcurrentHashMap<Context, Storage>();
 
-    private volatile ConcurrentHashMap<String, String> storage = new ConcurrentHashMap<String, String>();
+    private volatile ConcurrentMap<String, String> storage = new ConcurrentHashMap<String, String>();
 
     private CopyOnWriteArrayList<OnSharedPreferenceChangeListener> listeners =
         new CopyOnWriteArrayList<OnSharedPreferenceChangeListener>();
@@ -32,11 +34,11 @@ public class Storage implements SharedPreferences {
     private int DB_VERSION = 2;
     private String DB_NAME = "preferences_storage";
 
-    private ThreadLocal<ConcurrentHashMap<String, String>> workingStorage
-    = new ThreadLocal<ConcurrentHashMap<String, String>>();
+    private ThreadLocal<ConcurrentMap<String, String>> workingStorage
+    = new ThreadLocal<ConcurrentMap<String, String>>();
     private ThreadLocal<SQLiteDatabase> workingDB =
         new ThreadLocal<SQLiteDatabase>();
-    private ThreadLocal<ArrayList<String>> workingChangedKeys = new ThreadLocal<ArrayList<String>>();
+    private ThreadLocal<List<String>> workingChangedKeys = new ThreadLocal<List<String>>();
 
 
     private Context context = null;
@@ -202,7 +204,7 @@ public class Storage implements SharedPreferences {
     }
 
     private void keyChange(String key) {
-        ArrayList<String> changedKeys = workingChangedKeys.get();
+        List<String> changedKeys = workingChangedKeys.get();
         if (!changedKeys.contains(key)) {
             changedKeys.add(key);
         }
@@ -259,14 +261,14 @@ public class Storage implements SharedPreferences {
     }
 
     protected void doInTransaction(Runnable dbWork) {
-        ConcurrentHashMap<String, String> newStorage = new ConcurrentHashMap<String, String>();
+        ConcurrentMap<String, String> newStorage = new ConcurrentHashMap<String, String>();
         newStorage.putAll(storage);
         workingStorage.set(newStorage);
 
         SQLiteDatabase mDb = openDB();
         workingDB.set(mDb);
 
-        ArrayList<String> changedKeys = new ArrayList<String>();
+        List<String> changedKeys = new ArrayList<String>();
         workingChangedKeys.set(changedKeys);
 
         mDb.beginTransaction();
@@ -294,7 +296,11 @@ public class Storage implements SharedPreferences {
 
     //@Override
     public boolean contains(String key) {
-        return storage.contains(key);
+        // TODO this used to be ConcurrentHashMap#contains which is
+        // actually containsValue. But looking at the usage of this method,
+        // it's clear that containsKey is what's intended. Investigate if this
+        // was a bug previously. Looks like it was only used once, when upgrading
+        return storage.containsKey(key);
     }
 
     //@Override
diff --git a/src/com/fsck/k9/search/ConditionsTreeNode.java b/src/com/fsck/k9/search/ConditionsTreeNode.java
index 2db7eef47..3299c744e 100644
--- a/src/com/fsck/k9/search/ConditionsTreeNode.java
+++ b/src/com/fsck/k9/search/ConditionsTreeNode.java
@@ -256,7 +256,7 @@ public class ConditionsTreeNode implements Parcelable {
      * @return List of all nodes in subtree in preorder.
      */
     public List<ConditionsTreeNode> preorder() {
-        ArrayList<ConditionsTreeNode> result = new ArrayList<ConditionsTreeNode>();
+        List<ConditionsTreeNode> result = new ArrayList<ConditionsTreeNode>();
         Stack<ConditionsTreeNode> stack = new Stack<ConditionsTreeNode>();
         stack.push(this);
 
diff --git a/src/com/fsck/k9/search/LocalSearch.java b/src/com/fsck/k9/search/LocalSearch.java
index 0dbf861c3..68dddbf89 100644
--- a/src/com/fsck/k9/search/LocalSearch.java
+++ b/src/com/fsck/k9/search/LocalSearch.java
@@ -252,7 +252,7 @@ public class LocalSearch implements SearchSpecification {
      * real searches because of possible extra conditions to a folder requirement.
      */
     public List<String> getFolderNames() {
-        ArrayList<String> results = new ArrayList<String>();
+        List<String> results = new ArrayList<String>();
         for (ConditionsTreeNode node : mLeafSet) {
             if (node.mCondition.field == Searchfield.FOLDER &&
                     node.mCondition.attribute == Attribute.EQUALS) {
diff --git a/src/com/fsck/k9/service/NotificationActionService.java b/src/com/fsck/k9/service/NotificationActionService.java
index 791db4257..e4cad21c9 100644
--- a/src/com/fsck/k9/service/NotificationActionService.java
+++ b/src/com/fsck/k9/service/NotificationActionService.java
@@ -1,6 +1,7 @@
 package com.fsck.k9.service;
 
 import java.util.ArrayList;
+import java.util.List;
 
 import com.fsck.k9.Account;
 import com.fsck.k9.K9;
@@ -8,6 +9,7 @@ import com.fsck.k9.Preferences;
 import com.fsck.k9.activity.MessageCompose;
 import com.fsck.k9.activity.MessageReference;
 import com.fsck.k9.controller.MessagingController;
+import com.fsck.k9.helper.Utility;
 import com.fsck.k9.mail.Flag;
 import com.fsck.k9.mail.Message;
 
@@ -36,12 +38,12 @@ public class NotificationActionService extends CoreService {
     }
 
     public static PendingIntent getReadAllMessagesIntent(Context context, final Account account,
-            final ArrayList<MessageReference> refs) {
+            final List<MessageReference> refs) {
         Intent i = new Intent(context, NotificationActionService.class);
         i.putExtra(EXTRA_ACCOUNT, account.getUuid());
-        i.putExtra(EXTRA_MESSAGE_LIST, refs);
+        i.putExtra(EXTRA_MESSAGE_LIST, Utility.toSerializableList(refs));
         i.setAction(READ_ALL_ACTION);
-        
+
         return PendingIntent.getService(context, account.getAccountNumber(), i, PendingIntent.FLAG_UPDATE_CURRENT);
     }
 
@@ -54,10 +56,10 @@ public class NotificationActionService extends CoreService {
     }
 
     public static Intent getDeleteAllMessagesIntent(Context context, final Account account,
-            final ArrayList<MessageReference> refs) {
+            final List<MessageReference> refs) {
         Intent i = new Intent(context, NotificationActionService.class);
         i.putExtra(EXTRA_ACCOUNT, account.getUuid());
-        i.putExtra(EXTRA_MESSAGE_LIST, refs);
+        i.putExtra(EXTRA_MESSAGE_LIST, Utility.toSerializableList(refs));
         i.setAction(DELETE_ALL_ACTION);
 
         return i;
@@ -77,7 +79,7 @@ public class NotificationActionService extends CoreService {
                 if (K9.DEBUG)
                     Log.i(K9.LOG_TAG, "NotificationActionService marking messages as read");
 
-                ArrayList<MessageReference> refs =
+                List<MessageReference> refs =
                         intent.getParcelableArrayListExtra(EXTRA_MESSAGE_LIST);
                 for (MessageReference ref : refs) {
                     controller.setFlag(account, ref.folderName, ref.uid, Flag.SEEN, true);
@@ -86,9 +88,9 @@ public class NotificationActionService extends CoreService {
                 if (K9.DEBUG)
                     Log.i(K9.LOG_TAG, "NotificationActionService deleting messages");
 
-                ArrayList<MessageReference> refs =
+                List<MessageReference> refs =
                         intent.getParcelableArrayListExtra(EXTRA_MESSAGE_LIST);
-                ArrayList<Message> messages = new ArrayList<Message>();
+                List<Message> messages = new ArrayList<Message>();
 
                 for (MessageReference ref : refs) {
                     Message m = ref.restoreToLocalMessage(this);
@@ -121,7 +123,7 @@ public class NotificationActionService extends CoreService {
         } else {
             Log.w(K9.LOG_TAG, "Could not find account for notification action.");
         }
-        
+
         return START_NOT_STICKY;
     }
 }
diff --git a/src/com/fsck/k9/service/PollService.java b/src/com/fsck/k9/service/PollService.java
index f24f761de..0fbe8d4c0 100644
--- a/src/com/fsck/k9/service/PollService.java
+++ b/src/com/fsck/k9/service/PollService.java
@@ -12,6 +12,7 @@ import com.fsck.k9.helper.power.TracingPowerManager;
 import com.fsck.k9.helper.power.TracingPowerManager.TracingWakeLock;
 
 import java.util.HashMap;
+import java.util.Map;
 
 public class PollService extends CoreService {
     private static String START_SERVICE = "com.fsck.k9.service.PollService.startService";
@@ -77,7 +78,7 @@ public class PollService extends CoreService {
     }
 
     class Listener extends MessagingListener {
-        HashMap<String, Integer> accountsChecked = new HashMap<String, Integer>();
+        Map<String, Integer> accountsChecked = new HashMap<String, Integer>();
         private TracingWakeLock wakeLock = null;
         private int startId = -1;
 
diff --git a/src/com/fsck/k9/view/NonLockingScrollView.java b/src/com/fsck/k9/view/NonLockingScrollView.java
index 38e479ef8..5897c3b22 100644
--- a/src/com/fsck/k9/view/NonLockingScrollView.java
+++ b/src/com/fsck/k9/view/NonLockingScrollView.java
@@ -28,6 +28,7 @@ import android.webkit.WebView;
 import android.widget.ScrollView;
 
 import java.util.ArrayList;
+import java.util.List;
 
 /**
  * A {@link ScrollView} that will never lock scrolling in a particular direction.
@@ -59,7 +60,7 @@ public class NonLockingScrollView extends ScrollView {
     /**
      * The list of children who should always receive touch events, and not have them intercepted.
      */
-    private final ArrayList<View> mChildrenNeedingAllTouches = new ArrayList<View>();
+    private final List<View> mChildrenNeedingAllTouches = new ArrayList<View>();
 
     private boolean mSkipWebViewScroll = true;
 
@@ -122,7 +123,7 @@ public class NonLockingScrollView extends ScrollView {
     }
 
     private final Rect sHitFrame = new Rect();
-    private boolean isEventOverChild(MotionEvent ev, ArrayList<View> children) {
+    private boolean isEventOverChild(MotionEvent ev, List<View> children) {
         final int actionIndex = ev.getActionIndex();
         final float x = ev.getX(actionIndex) + getScrollX();
         final float y = ev.getY(actionIndex) + getScrollY();