W/System.err: java.lang.NullPointerException: Attempt to invoke interface method 'java.lang.String java.lang.CharSequence.toString()' on a null object reference W/System.err: at android.widget.ToastInjector.addAppName(ToastInjector.java:50) W/System.err: at android.widget.Toast.makeText(Toast.java:287) W/System.err: at android.widget.Toast.makeText(Toast.java:270) W/System.err: at com.android.rxjavaproject.MainActivity.show(MainActivity.java:105) W/System.err: at com.android.rxjavaproject.MainActivity.onCreate(MainActivity.java:98) W/System.err: at android.app.Activity.performCreate(Activity.java:7210) W/System.err: at android.app.Activity.performCreate(Activity.java:7201) W/System.err: at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1272) W/System.err: at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2926) W/System.err: at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3081) W/System.err: at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78) W/System.err: at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108) W/System.err: at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68) W/System.err: at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1831) W/System.err: at android.os.Handler.dispatchMessage(Handler.java:106) W/System.err: at android.os.Looper.loop(Looper.java:201) W/System.err: at android.app.ActivityThread.main(ActivityThread.java:6806) W/System.err: at java.lang.reflect.Method.invoke(Native Method) W/System.err: at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:547) W/System.err: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:873)