Core Class Android

//package uk.me.kjs.android.helloworld;
import android.app.Activity;
import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.telephony.*;
import android.os.Bundle;
import android.widget.TextView;
import android.widget.Toast;
public class Init extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        TextView tv = new TextView(this);
        TelephonyManager tm = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);
          String str = new String();
            String net = new String(); 
            
            switch(tm.getNetworkType())
            {
              case TelephonyManager.NETWORK_TYPE_1xRTT:
                net = "CDMA - 2000";
                break;
              case TelephonyManager.NETWORK_TYPE_CDMA:
                net = "CDMA";
                break;
              case TelephonyManager.NETWORK_TYPE_EDGE:
                net = "GSM - EDGE";
                break;
              case TelephonyManager.NETWORK_TYPE_EVDO_0:
                net = "CDMA - EVDO A";
                break;
              case TelephonyManager.NETWORK_TYPE_EVDO_A:
                net = "CDMA - EVDO A";
                break;
              case TelephonyManager.NETWORK_TYPE_GPRS:
                net = "GSM - GPRS";
                break;
              case TelephonyManager.NETWORK_TYPE_UMTS:
                net = "UMTS";
                break;
              case 8:
                net = "UMTS - HSDPA ";
                break;
              case 9:
                net = "UMTS - HSUPA ";
                break;
              case 10:
                net = "UMTS - HSPA ";
                break;
              case TelephonyManager.NETWORK_TYPE_UNKNOWN:
              default:
                net = "Unknown";
            }
            
            String home = new String();
            if (  tm.isNetworkRoaming()  == true)
            {
              home = "Roaming";
            }
            else
            {
              home = "Home";
            }
            
            
            
        str = "SIM Information";
        str += "\nName : " + tm.getSimOperatorName();
        str += "\nCode : " + tm.getSimOperator() + " (" + tm.getSimCountryIso() + ")";
        str += "\n";    
        str += "\nConnected Network";
        str += "\nName : " + tm.getNetworkOperatorName();
        str += "\nRoaming : " + home;
        str += "\nCode : " + tm.getNetworkOperator() + " (" + tm.getNetworkCountryIso() + ")";
        str += "\nType : " + net;
     
        
        tv.setTextSize(20);
        tv.setText(str);
        setContentView(tv);
        
        Context context = getApplicationContext();
        CharSequence text = "Hello toast!";
        int duration = Toast.LENGTH_SHORT;
        Toast toast = Toast.makeText(context, text, duration);
        toast.show();
     
    }
}