android - Keep service running in background even user clear memory -

i have service follows:

public class service extends service {     private static final string tag = "myservice";     @override     public void oncreate() {         super.oncreate();         log.d(tag, "oncreate");     }     @override     public ibinder onbind(intent intent) {         return null;     }     public void ondestroy() {         toast.maketext(this, "my service stopped", toast.length_long).show();         log.d(tag, "ondestroy");     }      @override     public int onstartcommand(intent intent, int flags, int startid)     {         intent intents = new intent(getbasecontext(),mainactivity.class);         intents.setflags(intent.flag_activity_new_task);         startactivity(intents);         toast.maketext(this, "my service started", toast.length_long).show();         log.d(tag, "onstart");         return start_not_sticky;     } } 

it worked well, , can check service running when go application setting. however, if clear applications long press home button , clear them. did not see running service. how can maintain service running in background, user clear apps or memory? thank all

this manifest

<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android"     package="com.example.hellobootservice"     android:permission="android.permission.receive_boot_completed">      <uses-permission android:name="android.permission.receive_boot_completed"></uses-permission>      <application         android:allowbackup="true"         android:icon="@mipmap/ic_launcher"         android:label="@string/app_name"         android:supportsrtl="true"         android:theme="@style/apptheme">         <activity android:name=".mainactivity">             <intent-filter>                 <action android:name="android.intent.action.main" />                  <category android:name="android.intent.category.launcher" />             </intent-filter>         </activity>         <receiver android:name=".autostart">             <intent-filter>                 <action android:name="android.intent.action.boot_completed" />             </intent-filter>         </receiver>         <service android:enabled="true"                 android:process=":hello"                 android:name=".service" />     </application>  </manifest> 

replace

return start_not_sticky; 

with

return start_sticky; 

inside onstartcommand().