Fix NPE
Synchronize access to locks
Add empty implementations to avoid crashes while loading

    java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.zegoggles.smssync/com.zegoggles.smssync.ComposeSmsActivity}: java.lang.ClassNotFoundException: Didn't find class "com.zegoggles.smssync.ComposeSmsActivity" on path: DexPathList[[zip file "/data/app/com.zegoggles.smssync-2.apk"],nativeLibraryDirectories=[/data/app-lib/com.zegoggles.smssync-2, /vendor/lib, /system/lib]]