Retain the Fragment object while rotating

Use onAttachFragment() in your Activity to reassign the object:

@Override
public void onAttachFragment(Fragment fragment) {
    if (fragment instanceof MyFragment)
        this.myFragment = (MyFragment) fragment;
}

By default Android will retain the fragment objects. In your code you are setting the homeFragment in your onCreate function. That is why it is allways some homeFragment or fl what ever that you set in onCreate.

Because whenever you rotate, the onCreate will execute and set your fragment object to the first one

So the easy solution for you is check whether savedInstanceState bundle is null or not and set the fragment object

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    if(null == savedInstanceState) {
        // set you initial fragment object 
    }
 }

You need to give your Fragment a unique tag, and check whether this Fragment is already added to your Activity already or not.

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    String tag = "my_fragment";
    FragmentManager fragmentManager = getFragmentManager();
    if(fragmentManager.findFragmentByTag(tag) == null) {
        FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction();
        Fragment homeFragment = new Home();
        fragmentTransaction.add(R.id.mainFragement, homeFragment, tag);
        fragmentTransaction.commit();
    }
}

Checking whether savedInstanceState is null is not a safe way to check whether your fragment is already set - it will work in most cases, but in some cases (such as when the device is on low memory), Android may kill your Activity, which could break your application.

To see this in action, tick "Don't keep activities" in the device's development options (the setting is available in Android 4.0+, not sure about earlier versions). When you open a new activity, your first activity is destroyed. When you return to it (by pressing back), it is created again, and savedInstanceState is not null. However, your fragment is not in the activity anymore, and you have to add it again.

EDIT - Showing the original principle but with SupportFragmentManager

public class ActivityAwesome extends AppCompatActivity
{
    private final String TAG = getClass().getSimpleName();
    private FragmentHome mHomeFragment;

    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_layout);

        FragmentManager fragmentManager = getSupportFragmentManager();
        Fragment fragment = fragmentManager.findFragmentByTag(TAG);
        if(fragment == null)
        {
            // Create the detail fragment and add it to the activity using a fragment transaction.
            mHomeFragment = new FragmentHome();
            fragmentManager.beginTransaction()
                    .add(R.id.fragment_container, mHomeFragment, TAG)
                    .commit();
        }
        else
        {
            // get our old fragment back !
            mHomeFragment = (FragmentHome)fragment;
        }
    }
}

this comes in especially useful if you want to manipulate the fragment (in this case mHomeFragment) after rotating your device