Use Intent to start your service

import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.widget.Toast;
//ww  w  .ja  v  a  2  s.  c  om
public class MyService extends Service {

    @Override
    public IBinder onBind(Intent arg0) {
        return null;
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        // We want this service to continue running until it is explicitly
        // stopped, so return sticky.
        Toast.makeText (this, "Service Started", Toast.LENGTH_LONG).show();
        return START_STICKY;
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        Toast.makeText (this, "Service Destroyed", Toast.LENGTH_LONG).show();
    }
}

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.java2s.Services"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk android:minSdkVersion="14" />

    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name" >
        <activity
         android:label="@string/app_name"
         android:name=".ServicesActivity" >
         <intent-filter >
             <action android:name="android.intent.action.MAIN" />

             <category android:name="android.intent.category.LAUNCHER" />
         </intent-filter>
     </activity>
     <service android:name=".MyService">
         <intent-filter>
            <action android:name="com.java2s.MyService" />
         </intent-filter>
     </service>
 </application>

</manifest>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

<Button android:id="@+id/btnStartService"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="Start Service"
    android:onClick="startService"/>

<Button android:id="@+id/btnStopService"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="Stop Service"
    android:onClick="stopService" />

</LinearLayout>

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
/*from  ww  w  . j  a v a 2  s  .  co m*/
public class MainActivity extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
    }

    public void startService(View view) {
        //startService(new Intent(getBaseContext(), MyService.class));
        //OR
        startService(new Intent("com.java2s.MyService"));
    }

    public void stopService(View view) {
       stopService(new Intent(getBaseContext(),MyService.class));
    }
}