title: How intent object keep/transfer data between two Activity in android?
body: <p>i have these two Activity and each in the separate file:</p>
  
  <pre><code> public class MainActivity extends AppCompatActivity {
          public final static String EXTRA_MESSAGE = "com.example.myfirstapp.MESSAGE";
          @Override
          protected void onCreate(Bundle savedInstanceState) {
              super.onCreate(savedInstanceState);
              setContentView(R.layout.activity_main);
          }
  
          /** Called when the user clicks the Send button */
          public void sendMessage(View view) {
              Intent intent = new Intent(this, DisplayMessageActivity.class);
              EditText editText = (EditText) findViewById(R.id.edit_message);
              String message = editText.getText().toString();
              intent.putExtra(EXTRA_MESSAGE, message);
              startActivity(intent);
          }
      }
  
      public class DisplayMessageActivity extends AppCompatActivity {
      @Override
      protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_display_message);
  
         Intent intent = getIntent();
         String message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);
         TextView textView = new TextView(this);
         textView.setTextSize(40);
         textView.setText(message);
  
         ViewGroup layout = (ViewGroup) findViewById(R.id.activity_display_message);
         layout.addView(textView);
      }
      }
  </code></pre>
  
  <p>in MainActivity we create <code>Intent</code> object and hold him some data ,
  in the <code>DisplayMessageActivity</code> we get this intent using <code>getIntent()</code> method ,
  and this method return to us <code>Intent</code> object 
  my question is how this method return to us the same Intent that we create in <code>MainActivity</code> ??</p>