Where to find this code(LISTING 2-1Hello World) in the tree in Eclipse

package com.paad.helloworld;
import android.app.Activity;
import android.os.Bundle;
public class MyActivity extends Activity {
/** Called when the Activity is first created. **/
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}

All code samples are in the Code Snippets, The Chapter, then in the folder that relates. Open it, go to SRC, and open the files. The sections are commented in there. It'll say "2-1 " etc, as it says so in the book.

Ok,but i like to know where is the code in the tree in Eclipse

I understand. To find it, you have to import the project you want, then go to the SRC folder.