diff --git a/core/java/android/app/ContextImpl.java b/core/java/android/app/ContextImpl.java
index af56cb4..831c298 100644
--- a/core/java/android/app/ContextImpl.java
+++ b/core/java/android/app/ContextImpl.java
@@ -272,10 +272,17 @@
 
     @UnsupportedAppUsage
     private Context mOuterContext;
+
+    private final Object mThemeLock = new Object();
+
     @UnsupportedAppUsage
+    @GuardedBy("mThemeLock")
     private int mThemeResource = 0;
+
     @UnsupportedAppUsage
+    @GuardedBy("mThemeLock")
     private Resources.Theme mTheme = null;
+
     @UnsupportedAppUsage
     private PackageManager mPackageManager;
     private Context mReceiverRestrictedContext = null;
@@ -288,7 +295,6 @@
 
     private ContentCaptureOptions mContentCaptureOptions = null;
 
-    private final Object mSync = new Object();
     /**
      * Indicates this {@link Context} can not handle UI components properly and is not associated
      * with a {@link Display} instance.
@@ -340,21 +346,18 @@
      */
     private boolean mOwnsToken = false;
 
-    @GuardedBy("mSync")
-    private File mDatabasesDir;
-    @GuardedBy("mSync")
-    @UnsupportedAppUsage
-    private File mPreferencesDir;
-    @GuardedBy("mSync")
-    private File mFilesDir;
-    @GuardedBy("mSync")
-    private File mCratesDir;
-    @GuardedBy("mSync")
-    private File mNoBackupFilesDir;
-    @GuardedBy("mSync")
-    private File mCacheDir;
-    @GuardedBy("mSync")
-    private File mCodeCacheDir;
+    private final Object mDirsLock = new Object();
+    private volatile File mDatabasesDir;
+    @UnsupportedAppUsage private volatile File mPreferencesDir;
+    private volatile File mFilesDir;
+    private volatile File mCratesDir;
+    private volatile File mNoBackupFilesDir;
+    private volatile File[] mExternalFilesDirs;
+    private volatile File[] mObbDirs;
+    private volatile File mCacheDir;
+    private volatile File mCodeCacheDir;
+    private volatile File[] mExternalCacheDirs;
+    private volatile File[] mExternalMediaDirs;
 
     // The system service cache for the system services that are cached per-ContextImpl.
     @UnsupportedAppUsage
@@ -458,7 +461,7 @@
 
     @Override
     public void setTheme(int resId) {
-        synchronized (mSync) {
+        synchronized (mThemeLock) {
             if (mThemeResource != resId) {
                 mThemeResource = resId;
                 initializeTheme();
@@ -468,14 +471,14 @@
 
     @Override
     public int getThemeResId() {
-        synchronized (mSync) {
+        synchronized (mThemeLock) {
             return mThemeResource;
         }
     }
 
     @Override
     public Resources.Theme getTheme() {
-        synchronized (mSync) {
+        synchronized (mThemeLock) {
             if (mTheme != null) {
                 return mTheme;
             }
@@ -488,6 +491,7 @@
         }
     }
 
+    @GuardedBy("mThemeLock")
     private void initializeTheme() {
         if (mTheme == null) {
             mTheme = mResources.newTheme();
@@ -731,12 +735,18 @@
 
     @UnsupportedAppUsage
     private File getPreferencesDir() {
-        synchronized (mSync) {
-            if (mPreferencesDir == null) {
-                mPreferencesDir = new File(getDataDir(), "shared_prefs");
+        File localPreferencesDir = mPreferencesDir;
+        if (localPreferencesDir == null) {
+            synchronized (mDirsLock) {
+                localPreferencesDir = mPreferencesDir;
+                if (localPreferencesDir == null) {
+                    localPreferencesDir = new File(getDataDir(), "shared_prefs");
+                    ensurePrivateDirExists(localPreferencesDir);
+                    mPreferencesDir = localPreferencesDir;
+                }
             }
-            return ensurePrivateDirExists(mPreferencesDir);
         }
+        return localPreferencesDir;
     }
 
     @Override
@@ -778,16 +788,16 @@
     /**
      * Common-path handling of app data dir creation
      */
-    private static File ensurePrivateDirExists(File file) {
-        return ensurePrivateDirExists(file, 0771, -1, null);
+    private static void ensurePrivateDirExists(File file) {
+        ensurePrivateDirExists(file, 0771, -1, null);
     }
 
-    private static File ensurePrivateCacheDirExists(File file, String xattr) {
+    private static void ensurePrivateCacheDirExists(File file, String xattr) {
         final int gid = UserHandle.getCacheAppGid(Process.myUid());
-        return ensurePrivateDirExists(file, 02771, gid, xattr);
+        ensurePrivateDirExists(file, 02771, gid, xattr);
     }
 
-    private static File ensurePrivateDirExists(File file, int mode, int gid, String xattr) {
+    private static void ensurePrivateDirExists(File file, int mode, int gid, String xattr) {
         if (!file.exists()) {
             final String path = file.getAbsolutePath();
             try {
@@ -815,17 +825,22 @@
                 }
             }
         }
-        return file;
     }
 
     @Override
     public File getFilesDir() {
-        synchronized (mSync) {
-            if (mFilesDir == null) {
-                mFilesDir = new File(getDataDir(), "files");
+        File localFilesDir = mFilesDir;
+        if (localFilesDir == null) {
+            localFilesDir = mFilesDir;
+            synchronized (mDirsLock) {
+                if (localFilesDir == null) {
+                    localFilesDir = new File(getDataDir(), "files");
+                    ensurePrivateDirExists(localFilesDir);
+                    mFilesDir = localFilesDir;
+                }
             }
-            return ensurePrivateDirExists(mFilesDir);
         }
+        return localFilesDir;
     }
 
     @Override
@@ -835,25 +850,37 @@
         final Path absoluteNormalizedCratePath = cratesRootPath.resolve(crateId)
                 .toAbsolutePath().normalize();
 
-        synchronized (mSync) {
-            if (mCratesDir == null) {
-                mCratesDir = cratesRootPath.toFile();
+        File localCratesDir = mCratesDir;
+        if (localCratesDir == null) {
+            synchronized (mDirsLock) {
+                localCratesDir = mCratesDir;
+                if (localCratesDir == null) {
+                    localCratesDir = cratesRootPath.toFile();
+                    ensurePrivateDirExists(localCratesDir);
+                    mCratesDir = localCratesDir;
+                }
             }
-            ensurePrivateDirExists(mCratesDir);
         }
 
-        File cratedDir = absoluteNormalizedCratePath.toFile();
-        return ensurePrivateDirExists(cratedDir);
+        File crateDir = absoluteNormalizedCratePath.toFile();
+        ensurePrivateDirExists(crateDir);
+        return crateDir;
     }
 
     @Override
     public File getNoBackupFilesDir() {
-        synchronized (mSync) {
-            if (mNoBackupFilesDir == null) {
-                mNoBackupFilesDir = new File(getDataDir(), "no_backup");
+        File localNoBackupFilesDir = mNoBackupFilesDir;
+        if (localNoBackupFilesDir == null) {
+            synchronized (mDirsLock) {
+                localNoBackupFilesDir = mNoBackupFilesDir;
+                if (localNoBackupFilesDir == null) {
+                    localNoBackupFilesDir = new File(getDataDir(), "no_backup");
+                    ensurePrivateDirExists(localNoBackupFilesDir);
+                    mNoBackupFilesDir = localNoBackupFilesDir;
+                }
             }
-            return ensurePrivateDirExists(mNoBackupFilesDir);
         }
+        return localNoBackupFilesDir;
     }
 
     @Override
@@ -865,13 +892,24 @@
 
     @Override
     public File[] getExternalFilesDirs(String type) {
-        synchronized (mSync) {
-            File[] dirs = Environment.buildExternalStorageAppFilesDirs(getPackageName());
-            if (type != null) {
-                dirs = Environment.buildPaths(dirs, type);
+        File[] localExternalFilesDirs = mExternalFilesDirs;
+        if (localExternalFilesDirs == null) {
+            synchronized (mDirsLock) {
+                localExternalFilesDirs = mExternalFilesDirs;
+                if (localExternalFilesDirs == null) {
+                    localExternalFilesDirs =
+                            Environment.buildExternalStorageAppFilesDirs(getPackageName());
+                    if (type != null) {
+                        localExternalFilesDirs =
+                                Environment.buildPaths(localExternalFilesDirs, type);
+                    }
+                    localExternalFilesDirs = ensureExternalDirsExistOrFilter(
+                            localExternalFilesDirs, true /* tryCreateInProcess */);
+                    mExternalFilesDirs = localExternalFilesDirs;
+                }
             }
-            return ensureExternalDirsExistOrFilter(dirs, true /* tryCreateInProcess */);
         }
+        return localExternalFilesDirs;
     }
 
     @Override
@@ -883,30 +921,51 @@
 
     @Override
     public File[] getObbDirs() {
-        synchronized (mSync) {
-            File[] dirs = Environment.buildExternalStorageAppObbDirs(getPackageName());
-            return ensureExternalDirsExistOrFilter(dirs, true /* tryCreateInProcess */);
+        File[] localObbDirs = mObbDirs;
+        if (mObbDirs == null) {
+            synchronized (mDirsLock) {
+                localObbDirs = mObbDirs;
+                if (localObbDirs == null) {
+                    localObbDirs = Environment.buildExternalStorageAppObbDirs(getPackageName());
+                    localObbDirs = ensureExternalDirsExistOrFilter(
+                            localObbDirs, true /* tryCreateInProcess */);
+                    mObbDirs = localObbDirs;
+                }
+            }
         }
+        return localObbDirs;
     }
 
     @Override
     public File getCacheDir() {
-        synchronized (mSync) {
-            if (mCacheDir == null) {
-                mCacheDir = new File(getDataDir(), "cache");
+        File localCacheDir = mCacheDir;
+        if (localCacheDir == null) {
+            synchronized (mDirsLock) {
+                localCacheDir = mCacheDir;
+                if (localCacheDir == null) {
+                    localCacheDir = new File(getDataDir(), "cache");
+                    ensurePrivateCacheDirExists(localCacheDir, XATTR_INODE_CACHE);
+                    mCacheDir = localCacheDir;
+                }
             }
-            return ensurePrivateCacheDirExists(mCacheDir, XATTR_INODE_CACHE);
         }
+        return localCacheDir;
     }
 
     @Override
     public File getCodeCacheDir() {
-        synchronized (mSync) {
-            if (mCodeCacheDir == null) {
-                mCodeCacheDir = getCodeCacheDirBeforeBind(getDataDir());
+        File localCodeCacheDir = mCodeCacheDir;
+        if (localCodeCacheDir == null) {
+            synchronized (mDirsLock) {
+                localCodeCacheDir = mCodeCacheDir;
+                if (localCodeCacheDir == null) {
+                    localCodeCacheDir = getCodeCacheDirBeforeBind(getDataDir());
+                    ensurePrivateCacheDirExists(localCodeCacheDir, XATTR_INODE_CODE_CACHE);
+                    mCodeCacheDir = localCodeCacheDir;
+                }
             }
-            return ensurePrivateCacheDirExists(mCodeCacheDir, XATTR_INODE_CODE_CACHE);
         }
+        return localCodeCacheDir;
     }
 
     /**
@@ -927,21 +986,37 @@
 
     @Override
     public File[] getExternalCacheDirs() {
-        synchronized (mSync) {
-            File[] dirs = Environment.buildExternalStorageAppCacheDirs(getPackageName());
-            // We don't try to create cache directories in-process, because they need special
-            // setup for accurate quota tracking. This ensures the cache dirs are always
-            // created through StorageManagerService.
-            return ensureExternalDirsExistOrFilter(dirs, false /* tryCreateInProcess */);
+        File[] localExternalCacheDirs = mExternalCacheDirs;
+        if (localExternalCacheDirs == null) {
+            synchronized (mDirsLock) {
+                localExternalCacheDirs = mExternalCacheDirs;
+                if (localExternalCacheDirs == null) {
+                    localExternalCacheDirs =
+                            Environment.buildExternalStorageAppCacheDirs(getPackageName());
+                    localExternalCacheDirs = ensureExternalDirsExistOrFilter(
+                            localExternalCacheDirs, false /* tryCreateInProcess */);
+                    mExternalCacheDirs = localExternalCacheDirs;
+                }
+            }
         }
+        return localExternalCacheDirs;
     }
 
     @Override
     public File[] getExternalMediaDirs() {
-        synchronized (mSync) {
-            File[] dirs = Environment.buildExternalStorageAppMediaDirs(getPackageName());
-            return ensureExternalDirsExistOrFilter(dirs, true /* tryCreateInProcess */);
+        File[] localExternalMediaDirs = mExternalMediaDirs;
+        if (localExternalMediaDirs == null) {
+            synchronized (mDirsLock) {
+                localExternalMediaDirs = mExternalMediaDirs;
+                if (localExternalMediaDirs == null) {
+                    localExternalMediaDirs = Environment.buildExternalStorageAppMediaDirs(getPackageName());
+                    localExternalMediaDirs = ensureExternalDirsExistOrFilter(
+                            localExternalMediaDirs, true /* tryCreateInProcess */);
+                    mExternalMediaDirs = localExternalMediaDirs;
+                }
+            }
         }
+        return localExternalMediaDirs;
     }
 
     /**
@@ -1040,16 +1115,22 @@
     }
 
     private File getDatabasesDir() {
-        synchronized (mSync) {
-            if (mDatabasesDir == null) {
-                if ("android".equals(getPackageName())) {
-                    mDatabasesDir = new File("/data/system");
-                } else {
-                    mDatabasesDir = new File(getDataDir(), "databases");
+        File localDatabasesDir = mDatabasesDir;
+        if (localDatabasesDir == null) {
+            synchronized (mDirsLock) {
+                localDatabasesDir = mDatabasesDir;
+                if (localDatabasesDir == null) {
+                    if ("android".equals(getPackageName())) {
+                        localDatabasesDir = new File("/data/system");
+                    } else {
+                        localDatabasesDir = new File(getDataDir(), "databases");
+                    }
+                    ensurePrivateDirExists(localDatabasesDir);
+                    mDatabasesDir = localDatabasesDir;
                 }
             }
-            return ensurePrivateDirExists(mDatabasesDir);
         }
+        return localDatabasesDir;
     }
 
     @Override