Alternate solution by using JobScheduler, it can start service in background in regular interval of time.
Firstly make class named as Util.java
import android.app.job.JobInfo;
import android.app.job.JobScheduler;
import android.content.ComponentName;
import android.content.Context;
public class Util {
// schedule the start of the service every 10 - 30 seconds
public static void schedulerJob(Context context) {
    ComponentName serviceComponent = new ComponentName(context,TestJobService.class);
    JobInfo.Builder builder = new JobInfo.Builder(0,serviceComponent);
    builder.setMinimumLatency(1*1000);    // wait at least
    builder.setOverrideDeadline(3*1000);  //delay time
    builder.setRequiredNetworkType(JobInfo.NETWORK_TYPE_UNMETERED);  // require unmetered network
    builder.setRequiresCharging(false);  // we don't care if the device is charging or not
    builder.setRequiresDeviceIdle(true); // device should be idle
    System.out.println("(scheduler Job");
    JobScheduler jobScheduler = null;
    if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.M) {
        jobScheduler = context.getSystemService(JobScheduler.class);
    }
    jobScheduler.schedule(builder.build());
   }
  }
Then, make JobService class named as TestJobService.java
import android.app.job.JobParameters;
import android.app.job.JobService;
import android.widget.Toast;
 
  /**
   * JobService to be scheduled by the JobScheduler.
   * start another service
   */ 
public class TestJobService extends JobService {
@Override
public boolean onStartJob(JobParameters params) {
    Util.schedulerJob(getApplicationContext()); // reschedule the job
    Toast.makeText(this, "Bg Service", Toast.LENGTH_SHORT).show();
    return true;
}
@Override
public boolean onStopJob(JobParameters params) {
    return true;
  }
 }
After that BroadCast Receiver class named ServiceReceiver.java
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
 public class ServiceReceiver extends BroadcastReceiver {
 @Override
public void onReceive(Context context, Intent intent) {
    Util.schedulerJob(context);
 }
}
Update Manifest file with service and receiver class code
<receiver android:name=".ServiceReceiver" >
        <intent-filter>
            <action android:name="android.intent.action.BOOT_COMPLETED" />
        </intent-filter>
    </receiver>
    <service
        android:name=".TestJobService"
        android:label="Word service"
        android:permission="android.permission.BIND_JOB_SERVICE" >
    </service>
Left main_intent launcher to mainActivity.java file which is created by default,  and changes in MainActivity.java file are
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Util.schedulerJob(getApplicationContext());
  }
 }
WOOAAH!! Background Service starts without Foreground service
[Edit]: You can use Work Manager for any type of background tasks in Android.