diff --git a/services/core/java/com/android/server/inputmethod/InputMethodManagerService.java b/services/core/java/com/android/server/inputmethod/InputMethodManagerService.java
index c207738a4f887..ba15a047af4ab 100644
--- a/services/core/java/com/android/server/inputmethod/InputMethodManagerService.java
+++ b/services/core/java/com/android/server/inputmethod/InputMethodManagerService.java
@@ -1495,8 +1495,7 @@ public final class InputMethodManagerService extends IInputMethodManager.Stub
 
         @Override
         public void onStart() {
-            LocalServices.addService(InputMethodManagerInternal.class,
-                    new LocalServiceImpl(mService));
+            mService.publishLocalService();
             publishBinderService(Context.INPUT_METHOD_SERVICE, mService, false /*allowIsolated*/,
                     DUMP_FLAG_PRIORITY_CRITICAL | DUMP_FLAG_PRIORITY_NORMAL | DUMP_FLAG_PROTO);
         }
@@ -4866,26 +4865,6 @@ public final class InputMethodManagerService extends IInputMethodManager.Stub
         return mCurrentSubtype;
     }
 
-    private List<InputMethodInfo> getInputMethodListAsUser(@UserIdInt int userId) {
-        synchronized (ImfLock.class) {
-            return getInputMethodListLocked(userId, DirectBootAwareness.AUTO);
-        }
-    }
-
-    private List<InputMethodInfo> getEnabledInputMethodListAsUser(@UserIdInt int userId) {
-        synchronized (ImfLock.class) {
-            return getEnabledInputMethodListLocked(userId);
-        }
-    }
-
-    private void onCreateInlineSuggestionsRequest(@UserIdInt int userId,
-            InlineSuggestionsRequestInfo requestInfo,
-            IInlineSuggestionsRequestCallback callback) {
-        synchronized (ImfLock.class) {
-            onCreateInlineSuggestionsRequestLocked(userId, requestInfo, callback);
-        }
-    }
-
     private ArrayMap<String, InputMethodInfo> queryMethodMapForUser(@UserIdInt int userId) {
         final ArrayMap<String, InputMethodInfo> methodMap = new ArrayMap<>();
         final ArrayList<InputMethodInfo> methodList = new ArrayList<>();
@@ -4897,161 +4876,153 @@ public final class InputMethodManagerService extends IInputMethodManager.Stub
         return methodMap;
     }
 
-    private boolean switchToInputMethod(String imeId, @UserIdInt int userId) {
-        synchronized (ImfLock.class) {
-            if (userId == mSettings.getCurrentUserId()) {
-                if (!mMethodMap.containsKey(imeId)
-                        || !mSettings.getEnabledInputMethodListLocked()
-                                .contains(mMethodMap.get(imeId))) {
-                    return false; // IME is not found or not enabled.
-                }
-                setInputMethodLocked(imeId, NOT_A_SUBTYPE_ID);
-                return true;
-            }
-            final ArrayMap<String, InputMethodInfo> methodMap = queryMethodMapForUser(userId);
-            final InputMethodSettings settings = new InputMethodSettings(
-                    mContext.getResources(), mContext.getContentResolver(), methodMap,
-                    userId, false);
-            if (!methodMap.containsKey(imeId)
-                    || !settings.getEnabledInputMethodListLocked()
-                            .contains(methodMap.get(imeId))) {
+    @GuardedBy("ImfLock.class")
+    private boolean switchToInputMethodLocked(String imeId, @UserIdInt int userId) {
+        if (userId == mSettings.getCurrentUserId()) {
+            if (!mMethodMap.containsKey(imeId)
+                    || !mSettings.getEnabledInputMethodListLocked()
+                            .contains(mMethodMap.get(imeId))) {
                 return false; // IME is not found or not enabled.
             }
-            settings.putSelectedInputMethod(imeId);
-            settings.putSelectedSubtype(NOT_A_SUBTYPE_ID);
+            setInputMethodLocked(imeId, NOT_A_SUBTYPE_ID);
             return true;
         }
+        final ArrayMap<String, InputMethodInfo> methodMap = queryMethodMapForUser(userId);
+        final InputMethodSettings settings = new InputMethodSettings(
+                mContext.getResources(), mContext.getContentResolver(), methodMap,
+                userId, false);
+        if (!methodMap.containsKey(imeId)
+                || !settings.getEnabledInputMethodListLocked()
+                        .contains(methodMap.get(imeId))) {
+            return false; // IME is not found or not enabled.
+        }
+        settings.putSelectedInputMethod(imeId);
+        settings.putSelectedSubtype(NOT_A_SUBTYPE_ID);
+        return true;
     }
 
-    private boolean setInputMethodEnabled(String imeId, boolean enabled, @UserIdInt int userId) {
-        synchronized (ImfLock.class) {
-            if (userId == mSettings.getCurrentUserId()) {
-                if (!mMethodMap.containsKey(imeId)) {
-                    return false; // IME is not found.
-                }
-                setInputMethodEnabledLocked(imeId, enabled);
-                return true;
-            }
-            final ArrayMap<String, InputMethodInfo> methodMap = queryMethodMapForUser(userId);
-            final InputMethodSettings settings = new InputMethodSettings(
-                    mContext.getResources(), mContext.getContentResolver(), methodMap,
-                    userId, false);
-            if (!methodMap.containsKey(imeId)) {
-                return false; // IME is not found.
-            }
-            if (enabled) {
-                if (!settings.getEnabledInputMethodListLocked().contains(methodMap.get(imeId))) {
-                    settings.appendAndPutEnabledInputMethodLocked(imeId, false);
-                }
-            } else {
-                settings.buildAndPutEnabledInputMethodsStrRemovingIdLocked(
-                        new StringBuilder(),
-                        settings.getEnabledInputMethodsAndSubtypeListLocked(), imeId);
-            }
-            return true;
-        }
+    private void publishLocalService() {
+        LocalServices.addService(InputMethodManagerInternal.class, new LocalServiceImpl());
     }
 
-    private boolean transferTouchFocusToImeWindow(@NonNull IBinder sourceInputToken,
-            int displayId) {
-        //TODO(b/150843766): Check if Input Token is valid.
-        final IBinder curHostInputToken;
-        synchronized (ImfLock.class) {
-            if (displayId != mCurTokenDisplayId || mCurHostInputToken == null) {
-                return false;
-            }
-            curHostInputToken = mCurHostInputToken;
-        }
-        return mInputManagerInternal.transferTouchFocus(sourceInputToken, curHostInputToken);
-    }
-
-    private void reportImeControl(@Nullable IBinder windowToken, boolean imeParentChanged) {
-        synchronized (ImfLock.class) {
-            if (mCurFocusedWindow != windowToken) {
-                // mCurPerceptible was set by the focused window, but it is no longer in control,
-                // so we reset mCurPerceptible.
-                mCurPerceptible = true;
-            }
-            if (imeParentChanged) {
-                // Hide the IME method menu earlier when the IME surface parent will change in
-                // case seeing the dialog dismiss flickering during the next focused window
-                // starting the input connection.
-                mMenuController.hideInputMethodMenu();
-            }
-        }
-    }
-
-    private static final class LocalServiceImpl extends InputMethodManagerInternal {
-        @NonNull
-        private final InputMethodManagerService mService;
-
-        LocalServiceImpl(@NonNull InputMethodManagerService service) {
-            mService = service;
-        }
+    private final class LocalServiceImpl extends InputMethodManagerInternal {
 
         @Override
         public void setInteractive(boolean interactive) {
             // Do everything in handler so as not to block the caller.
-            mService.mHandler.obtainMessage(MSG_SET_INTERACTIVE, interactive ? 1 : 0, 0)
-                    .sendToTarget();
+            mHandler.obtainMessage(MSG_SET_INTERACTIVE, interactive ? 1 : 0, 0).sendToTarget();
         }
 
         @Override
         public void hideCurrentInputMethod(@SoftInputShowHideReason int reason) {
-            mService.mHandler.removeMessages(MSG_HIDE_CURRENT_INPUT_METHOD);
-            mService.mHandler.obtainMessage(MSG_HIDE_CURRENT_INPUT_METHOD, reason).sendToTarget();
+            mHandler.removeMessages(MSG_HIDE_CURRENT_INPUT_METHOD);
+            mHandler.obtainMessage(MSG_HIDE_CURRENT_INPUT_METHOD, reason).sendToTarget();
         }
 
         @Override
         public List<InputMethodInfo> getInputMethodListAsUser(@UserIdInt int userId) {
-            return mService.getInputMethodListAsUser(userId);
+            synchronized (ImfLock.class) {
+                return getInputMethodListLocked(userId, DirectBootAwareness.AUTO);
+            }
         }
 
         @Override
         public List<InputMethodInfo> getEnabledInputMethodListAsUser(@UserIdInt int userId) {
-            return mService.getEnabledInputMethodListAsUser(userId);
+            synchronized (ImfLock.class) {
+                return getEnabledInputMethodListLocked(userId);
+            }
         }
 
         @Override
         public void onCreateInlineSuggestionsRequest(@UserIdInt int userId,
                 InlineSuggestionsRequestInfo requestInfo, IInlineSuggestionsRequestCallback cb) {
-            mService.onCreateInlineSuggestionsRequest(userId, requestInfo, cb);
+            synchronized (ImfLock.class) {
+                onCreateInlineSuggestionsRequestLocked(userId, requestInfo, cb);
+            }
         }
 
         @Override
         public boolean switchToInputMethod(String imeId, @UserIdInt int userId) {
-            return mService.switchToInputMethod(imeId, userId);
+            synchronized (ImfLock.class) {
+                return switchToInputMethodLocked(imeId, userId);
+            }
         }
 
         @Override
         public boolean setInputMethodEnabled(String imeId, boolean enabled, @UserIdInt int userId) {
-            return mService.setInputMethodEnabled(imeId, enabled, userId);
+            synchronized (ImfLock.class) {
+                if (userId == mSettings.getCurrentUserId()) {
+                    if (!mMethodMap.containsKey(imeId)) {
+                        return false; // IME is not found.
+                    }
+                    setInputMethodEnabledLocked(imeId, enabled);
+                    return true;
+                }
+                final ArrayMap<String, InputMethodInfo> methodMap = queryMethodMapForUser(userId);
+                final InputMethodSettings settings = new InputMethodSettings(
+                        mContext.getResources(), mContext.getContentResolver(), methodMap,
+                        userId, false);
+                if (!methodMap.containsKey(imeId)) {
+                    return false; // IME is not found.
+                }
+                if (enabled) {
+                    if (!settings.getEnabledInputMethodListLocked().contains(
+                            methodMap.get(imeId))) {
+                        settings.appendAndPutEnabledInputMethodLocked(imeId, false);
+                    }
+                } else {
+                    settings.buildAndPutEnabledInputMethodsStrRemovingIdLocked(
+                            new StringBuilder(),
+                            settings.getEnabledInputMethodsAndSubtypeListLocked(), imeId);
+                }
+                return true;
+            }
         }
 
         @Override
         public void registerInputMethodListListener(InputMethodListListener listener) {
-            mService.mInputMethodListListeners.addIfAbsent(listener);
+            mInputMethodListListeners.addIfAbsent(listener);
         }
 
         @Override
         public boolean transferTouchFocusToImeWindow(@NonNull IBinder sourceInputToken,
                 int displayId) {
-            return mService.transferTouchFocusToImeWindow(sourceInputToken, displayId);
+            //TODO(b/150843766): Check if Input Token is valid.
+            final IBinder curHostInputToken;
+            synchronized (ImfLock.class) {
+                if (displayId != mCurTokenDisplayId || mCurHostInputToken == null) {
+                    return false;
+                }
+                curHostInputToken = mCurHostInputToken;
+            }
+            return mInputManagerInternal.transferTouchFocus(sourceInputToken, curHostInputToken);
         }
 
         @Override
         public void reportImeControl(@Nullable IBinder windowToken, boolean imeParentChanged) {
-            mService.reportImeControl(windowToken, imeParentChanged);
+            synchronized (ImfLock.class) {
+                if (mCurFocusedWindow != windowToken) {
+                    // mCurPerceptible was set by the focused window, but it is no longer in
+                    // control, so we reset mCurPerceptible.
+                    mCurPerceptible = true;
+                }
+                if (imeParentChanged) {
+                    // Hide the IME method menu earlier when the IME surface parent will change in
+                    // case seeing the dialog dismiss flickering during the next focused window
+                    // starting the input connection.
+                    mMenuController.hideInputMethodMenu();
+                }
+            }
         }
 
         @Override
         public void removeImeSurface() {
-            mService.mHandler.obtainMessage(MSG_REMOVE_IME_SURFACE).sendToTarget();
+            mHandler.obtainMessage(MSG_REMOVE_IME_SURFACE).sendToTarget();
         }
 
         @Override
         public void updateImeWindowStatus(boolean disableImeIcon) {
-            mService.mHandler.obtainMessage(MSG_UPDATE_IME_WINDOW_STATUS, disableImeIcon ? 1 : 0, 0)
+            mHandler.obtainMessage(MSG_UPDATE_IME_WINDOW_STATUS, disableImeIcon ? 1 : 0, 0)
                     .sendToTarget();
         }
     }
@@ -5689,7 +5660,7 @@ public final class InputMethodManagerService extends IInputMethodManager.Stub
                 if (!userHasDebugPriv(userId, shellCommand)) {
                     continue;
                 }
-                boolean failedToSelectUnknownIme = !switchToInputMethod(imeId, userId);
+                boolean failedToSelectUnknownIme = !switchToInputMethodLocked(imeId, userId);
                 if (failedToSelectUnknownIme) {
                     error.print("Unknown input method ");
                     error.print(imeId);