Problem mit Hello World

package BST.HelloWorld;


import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;




public class HelloWorld extends Activity {
	   /** Called when the activity is first created. */
	   @Override
	   public void onCreate(Bundle savedInstanceState) {
	   	super.onCreate(savedInstanceState);
	   	TextView tv = new TextView(this);
	   	tv.setText("Hello World");
	   	setContentView(tv);
	   }
	}