data_binding_include_layout_activity.java

public class UserDetailActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        DataBindingIncludeMainLayout mBinding = DataBindingUtil
                .setContentView(this, R.layout.data_binding_include_main_layout);

        User user = new User("username", "password");

        mBinding.setMainUser(user);
    }
}

How to import DataBindingUtil and DataBindingIncludeMainLayout?