调用方法时，“ this”在Java中如何工作？

究竟如何this.C()运作？方法C是非静态的，因此必须通过实例进行调用。这指的是当前对象，但是什么对象以及如何创建？我没有显式创建一个对象，所以编译是否隐式地在后台创建了一个对象？

public class MainActivity extends Activity {
public static final String EXTRA_MESSAGE = "com.example.myfirstapp.MESSAGE";
    @Override
 protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        this.C();


    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {

        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;

    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if(id ==R.id.action_search){
            this.openSearch();
        }
        else if (id == R.id.action_settings) {
           // openSettings();
        }
        return super.onOptionsItemSelected(item);
    }
    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 void C(){
}
    public void openSearch(){
        getActionBar().hide();
    }

}