Add log.d hint (#26334)

guide/english/android-development/core-components/index.md

@@ -47,6 +47,9 @@ An _activity_ is a component that has a user interface and represents a single s
 This call is often used when the user hits the back button, or closes the instance of the app.
 
 #### Sample code to understand Activity Lifecycle
+
+You can print in log console using Log.d() method.
+
 ``` java
 import android.app.Activity;
 import android.os.Bundle;