To be @Nullable or @NonNull, that is the question.

Bug: 126699288, 126699496, 126700389
Bug: 126700085, 126701638, 126702005, 126700497
Test: manual
Change-Id: Idcbc2722ddcf014a9e5cef14321b4e2ce30adf9c
diff --git a/api/current.txt b/api/current.txt
index a888b08..a529a0f 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -13072,19 +13072,19 @@
     method public String buildUnionSubQuery(String, String[], java.util.Set<java.lang.String>, int, String, String, String, String);
     method @Deprecated public String buildUnionSubQuery(String, String[], java.util.Set<java.lang.String>, int, String, String, String[], String, String);
     method public int delete(@NonNull android.database.sqlite.SQLiteDatabase, @Nullable String, @Nullable String[]);
-    method public android.database.sqlite.SQLiteDatabase.CursorFactory getCursorFactory();
+    method @Nullable public android.database.sqlite.SQLiteDatabase.CursorFactory getCursorFactory();
     method public boolean getDistinct();
-    method public java.util.Map<java.lang.String,java.lang.String> getProjectionMap();
+    method @Nullable public java.util.Map<java.lang.String,java.lang.String> getProjectionMap();
     method public boolean getStrict();
-    method public String getTables();
+    method @Nullable public String getTables();
     method public android.database.Cursor query(android.database.sqlite.SQLiteDatabase, String[], String, String[], String, String, String);
     method public android.database.Cursor query(android.database.sqlite.SQLiteDatabase, String[], String, String[], String, String, String, String);
     method public android.database.Cursor query(android.database.sqlite.SQLiteDatabase, String[], String, String[], String, String, String, String, android.os.CancellationSignal);
-    method public void setCursorFactory(android.database.sqlite.SQLiteDatabase.CursorFactory);
+    method public void setCursorFactory(@Nullable android.database.sqlite.SQLiteDatabase.CursorFactory);
     method public void setDistinct(boolean);
-    method public void setProjectionMap(java.util.Map<java.lang.String,java.lang.String>);
+    method public void setProjectionMap(@Nullable java.util.Map<java.lang.String,java.lang.String>);
     method public void setStrict(boolean);
-    method public void setTables(String);
+    method public void setTables(@Nullable String);
     method public int update(@NonNull android.database.sqlite.SQLiteDatabase, @NonNull android.content.ContentValues, @Nullable String, @Nullable String[]);
   }
 
@@ -34585,7 +34585,7 @@
     method public static java.io.File getExternalStoragePublicDirectory(String);
     method public static String getExternalStorageState();
     method public static String getExternalStorageState(java.io.File);
-    method public static java.io.File getRootDirectory();
+    method @NonNull public static java.io.File getRootDirectory();
     method @Deprecated public static String getStorageState(java.io.File);
     method public static boolean isExternalStorageEmulated();
     method public static boolean isExternalStorageEmulated(java.io.File);
@@ -35311,27 +35311,27 @@
     ctor public StrictMode.ThreadPolicy.Builder();
     ctor public StrictMode.ThreadPolicy.Builder(android.os.StrictMode.ThreadPolicy);
     method public android.os.StrictMode.ThreadPolicy build();
-    method public android.os.StrictMode.ThreadPolicy.Builder detectAll();
-    method public android.os.StrictMode.ThreadPolicy.Builder detectCustomSlowCalls();
-    method public android.os.StrictMode.ThreadPolicy.Builder detectDiskReads();
-    method public android.os.StrictMode.ThreadPolicy.Builder detectDiskWrites();
-    method public android.os.StrictMode.ThreadPolicy.Builder detectNetwork();
-    method public android.os.StrictMode.ThreadPolicy.Builder detectResourceMismatches();
-    method public android.os.StrictMode.ThreadPolicy.Builder detectUnbufferedIo();
-    method public android.os.StrictMode.ThreadPolicy.Builder penaltyDeath();
-    method public android.os.StrictMode.ThreadPolicy.Builder penaltyDeathOnNetwork();
-    method public android.os.StrictMode.ThreadPolicy.Builder penaltyDialog();
-    method public android.os.StrictMode.ThreadPolicy.Builder penaltyDropBox();
-    method public android.os.StrictMode.ThreadPolicy.Builder penaltyFlashScreen();
-    method public android.os.StrictMode.ThreadPolicy.Builder penaltyListener(@NonNull java.util.concurrent.Executor, @NonNull android.os.StrictMode.OnThreadViolationListener);
-    method public android.os.StrictMode.ThreadPolicy.Builder penaltyLog();
-    method public android.os.StrictMode.ThreadPolicy.Builder permitAll();
-    method public android.os.StrictMode.ThreadPolicy.Builder permitCustomSlowCalls();
-    method public android.os.StrictMode.ThreadPolicy.Builder permitDiskReads();
-    method public android.os.StrictMode.ThreadPolicy.Builder permitDiskWrites();
-    method public android.os.StrictMode.ThreadPolicy.Builder permitNetwork();
-    method public android.os.StrictMode.ThreadPolicy.Builder permitResourceMismatches();
-    method public android.os.StrictMode.ThreadPolicy.Builder permitUnbufferedIo();
+    method @NonNull public android.os.StrictMode.ThreadPolicy.Builder detectAll();
+    method @NonNull public android.os.StrictMode.ThreadPolicy.Builder detectCustomSlowCalls();
+    method @NonNull public android.os.StrictMode.ThreadPolicy.Builder detectDiskReads();
+    method @NonNull public android.os.StrictMode.ThreadPolicy.Builder detectDiskWrites();
+    method @NonNull public android.os.StrictMode.ThreadPolicy.Builder detectNetwork();
+    method @NonNull public android.os.StrictMode.ThreadPolicy.Builder detectResourceMismatches();
+    method @NonNull public android.os.StrictMode.ThreadPolicy.Builder detectUnbufferedIo();
+    method @NonNull public android.os.StrictMode.ThreadPolicy.Builder penaltyDeath();
+    method @NonNull public android.os.StrictMode.ThreadPolicy.Builder penaltyDeathOnNetwork();
+    method @NonNull public android.os.StrictMode.ThreadPolicy.Builder penaltyDialog();
+    method @NonNull public android.os.StrictMode.ThreadPolicy.Builder penaltyDropBox();
+    method @NonNull public android.os.StrictMode.ThreadPolicy.Builder penaltyFlashScreen();
+    method @NonNull public android.os.StrictMode.ThreadPolicy.Builder penaltyListener(@NonNull java.util.concurrent.Executor, @NonNull android.os.StrictMode.OnThreadViolationListener);
+    method @NonNull public android.os.StrictMode.ThreadPolicy.Builder penaltyLog();
+    method @NonNull public android.os.StrictMode.ThreadPolicy.Builder permitAll();
+    method @NonNull public android.os.StrictMode.ThreadPolicy.Builder permitCustomSlowCalls();
+    method @NonNull public android.os.StrictMode.ThreadPolicy.Builder permitDiskReads();
+    method @NonNull public android.os.StrictMode.ThreadPolicy.Builder permitDiskWrites();
+    method @NonNull public android.os.StrictMode.ThreadPolicy.Builder permitNetwork();
+    method @NonNull public android.os.StrictMode.ThreadPolicy.Builder permitResourceMismatches();
+    method @NonNull public android.os.StrictMode.ThreadPolicy.Builder permitUnbufferedIo();
   }
 
   public static final class StrictMode.VmPolicy {
@@ -35342,26 +35342,26 @@
     ctor public StrictMode.VmPolicy.Builder();
     ctor public StrictMode.VmPolicy.Builder(android.os.StrictMode.VmPolicy);
     method public android.os.StrictMode.VmPolicy build();
-    method public android.os.StrictMode.VmPolicy.Builder detectActivityLeaks();
-    method public android.os.StrictMode.VmPolicy.Builder detectAll();
-    method public android.os.StrictMode.VmPolicy.Builder detectCleartextNetwork();
-    method public android.os.StrictMode.VmPolicy.Builder detectContentUriWithoutPermission();
-    method public android.os.StrictMode.VmPolicy.Builder detectCredentialProtectedWhileLocked();
-    method public android.os.StrictMode.VmPolicy.Builder detectFileUriExposure();
-    method public android.os.StrictMode.VmPolicy.Builder detectImplicitDirectBoot();
-    method public android.os.StrictMode.VmPolicy.Builder detectLeakedClosableObjects();
-    method public android.os.StrictMode.VmPolicy.Builder detectLeakedRegistrationObjects();
-    method public android.os.StrictMode.VmPolicy.Builder detectLeakedSqlLiteObjects();
-    method public android.os.StrictMode.VmPolicy.Builder detectNonSdkApiUsage();
-    method public android.os.StrictMode.VmPolicy.Builder detectUntaggedSockets();
-    method public android.os.StrictMode.VmPolicy.Builder penaltyDeath();
-    method public android.os.StrictMode.VmPolicy.Builder penaltyDeathOnCleartextNetwork();
-    method public android.os.StrictMode.VmPolicy.Builder penaltyDeathOnFileUriExposure();
-    method public android.os.StrictMode.VmPolicy.Builder penaltyDropBox();
-    method public android.os.StrictMode.VmPolicy.Builder penaltyListener(@NonNull java.util.concurrent.Executor, @NonNull android.os.StrictMode.OnVmViolationListener);
-    method public android.os.StrictMode.VmPolicy.Builder penaltyLog();
-    method public android.os.StrictMode.VmPolicy.Builder permitNonSdkApiUsage();
-    method public android.os.StrictMode.VmPolicy.Builder setClassInstanceLimit(Class, int);
+    method @NonNull public android.os.StrictMode.VmPolicy.Builder detectActivityLeaks();
+    method @NonNull public android.os.StrictMode.VmPolicy.Builder detectAll();
+    method @NonNull public android.os.StrictMode.VmPolicy.Builder detectCleartextNetwork();
+    method @NonNull public android.os.StrictMode.VmPolicy.Builder detectContentUriWithoutPermission();
+    method @NonNull public android.os.StrictMode.VmPolicy.Builder detectCredentialProtectedWhileLocked();
+    method @NonNull public android.os.StrictMode.VmPolicy.Builder detectFileUriExposure();
+    method @NonNull public android.os.StrictMode.VmPolicy.Builder detectImplicitDirectBoot();
+    method @NonNull public android.os.StrictMode.VmPolicy.Builder detectLeakedClosableObjects();
+    method @NonNull public android.os.StrictMode.VmPolicy.Builder detectLeakedRegistrationObjects();
+    method @NonNull public android.os.StrictMode.VmPolicy.Builder detectLeakedSqlLiteObjects();
+    method @NonNull public android.os.StrictMode.VmPolicy.Builder detectNonSdkApiUsage();
+    method @NonNull public android.os.StrictMode.VmPolicy.Builder detectUntaggedSockets();
+    method @NonNull public android.os.StrictMode.VmPolicy.Builder penaltyDeath();
+    method @NonNull public android.os.StrictMode.VmPolicy.Builder penaltyDeathOnCleartextNetwork();
+    method @NonNull public android.os.StrictMode.VmPolicy.Builder penaltyDeathOnFileUriExposure();
+    method @NonNull public android.os.StrictMode.VmPolicy.Builder penaltyDropBox();
+    method @NonNull public android.os.StrictMode.VmPolicy.Builder penaltyListener(@NonNull java.util.concurrent.Executor, @NonNull android.os.StrictMode.OnVmViolationListener);
+    method @NonNull public android.os.StrictMode.VmPolicy.Builder penaltyLog();
+    method @NonNull public android.os.StrictMode.VmPolicy.Builder permitNonSdkApiUsage();
+    method @NonNull public android.os.StrictMode.VmPolicy.Builder setClassInstanceLimit(Class, int);
   }
 
   public final class SystemClock {
@@ -38407,10 +38407,10 @@
 
   public final class MediaStore {
     ctor public MediaStore();
-    method @NonNull public static java.util.Set<java.lang.String> getAllVolumeNames(android.content.Context);
-    method public static android.net.Uri getDocumentUri(android.content.Context, android.net.Uri);
+    method @NonNull public static java.util.Set<java.lang.String> getAllVolumeNames(@NonNull android.content.Context);
+    method @Nullable public static android.net.Uri getDocumentUri(@NonNull android.content.Context, @NonNull android.net.Uri);
     method public static android.net.Uri getMediaScannerUri();
-    method public static android.net.Uri getMediaUri(android.content.Context, android.net.Uri);
+    method @Nullable public static android.net.Uri getMediaUri(@NonNull android.content.Context, @NonNull android.net.Uri);
     method public static String getVersion(android.content.Context);
     method @NonNull public static String getVolumeName(@NonNull android.net.Uri);
     method @NonNull public static android.net.Uri setIncludePending(@NonNull android.net.Uri);
diff --git a/api/removed.txt b/api/removed.txt
index 40b1316..31dda47 100644
--- a/api/removed.txt
+++ b/api/removed.txt
@@ -352,11 +352,11 @@
   }
 
   public static final class StrictMode.ThreadPolicy.Builder {
-    method public android.os.StrictMode.ThreadPolicy.Builder penaltyListener(@NonNull android.os.StrictMode.OnThreadViolationListener, @NonNull java.util.concurrent.Executor);
+    method @NonNull public android.os.StrictMode.ThreadPolicy.Builder penaltyListener(@NonNull android.os.StrictMode.OnThreadViolationListener, @NonNull java.util.concurrent.Executor);
   }
 
   public static final class StrictMode.VmPolicy.Builder {
-    method public android.os.StrictMode.VmPolicy.Builder penaltyListener(@NonNull android.os.StrictMode.OnVmViolationListener, @NonNull java.util.concurrent.Executor);
+    method @NonNull public android.os.StrictMode.VmPolicy.Builder penaltyListener(@NonNull android.os.StrictMode.OnVmViolationListener, @NonNull java.util.concurrent.Executor);
   }
 
   public final class SystemClock {
diff --git a/api/system-current.txt b/api/system-current.txt
index 8325cbc..ec7cea9 100644
--- a/api/system-current.txt
+++ b/api/system-current.txt
@@ -5210,11 +5210,11 @@
   }
 
   public class Environment {
-    method public static java.io.File getOdmDirectory();
-    method public static java.io.File getOemDirectory();
-    method public static java.io.File getProductDirectory();
-    method public static java.io.File getProductServicesDirectory();
-    method public static java.io.File getVendorDirectory();
+    method @NonNull public static java.io.File getOdmDirectory();
+    method @NonNull public static java.io.File getOemDirectory();
+    method @NonNull public static java.io.File getProductDirectory();
+    method @NonNull public static java.io.File getProductServicesDirectory();
+    method @NonNull public static java.io.File getVendorDirectory();
   }
 
   public class HidlSupport {
diff --git a/api/test-current.txt b/api/test-current.txt
index c5e535e..89a2a4c 100644
--- a/api/test-current.txt
+++ b/api/test-current.txt
@@ -1416,8 +1416,8 @@
 
   public class Environment {
     method public static java.io.File buildPath(java.io.File, java.lang.String...);
-    method public static java.io.File getProductDirectory();
-    method public static java.io.File getStorageDirectory();
+    method @NonNull public static java.io.File getProductDirectory();
+    method @NonNull public static java.io.File getStorageDirectory();
   }
 
   public final class FileUtils {
@@ -1666,7 +1666,7 @@
   }
 
   public static final class StrictMode.ThreadPolicy.Builder {
-    method public android.os.StrictMode.ThreadPolicy.Builder detectExplicitGc();
+    method @NonNull public android.os.StrictMode.ThreadPolicy.Builder detectExplicitGc();
   }
 
   public static final class StrictMode.ViolationInfo implements android.os.Parcelable {