[Demonstration 1]

[Buggy Method]
private Fragment switchToFragment(String fragmentName, Bundle args, boolean validate, boolean addToBackStack, int titleResId, CharSequence title, boolean withTransition) {
    if (validate && !isValidFragment(fragmentName)) {
        throw new IllegalArgumentException("Invalid fragment for this activity: " + fragmentName);
    }
    Fragment f = Fragment.instantiate(this, fragmentName, args);
    FragmentTransaction transaction = getFragmentManager().beginTransaction();
    transaction.replace(R.id.main_content, f);
    if (withTransition) {
        TransitionManager.beginDelayedTransition(mContent);
    }
    if (addToBackStack) {
        transaction.addToBackStack(SettingsActivity.BACK_STACK_PREFS);
    }
    if (titleResId > 0) {
        transaction.setBreadCrumbTitle(titleResId);
    } else if (title != null) {
        transaction.setBreadCrumbTitle(title);
    }
    transaction.commitAllowingStateLoss();
    getFragmentManager().executePendingTransactions();
    return f;
}

[Buggy Hunk]
transaction.replace(R.id.main_content, f);

[Patch]
transaction.replace(mMainContentId, f);

[Demonstration 2]

[Buggy Method]
@SuppressLint("NewApi")
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_movie_detalis);
    String transitionName = null;
    if (Utilities.isLollipopandAbove()) {
        postponeEnterTransition();
        transitionName = getIntent().getStringExtra("transition");
    }
    Movie movie = getIntent().getParcelableExtra(getString(R.string.movie_details_extra_key));
    if (savedInstanceState == null) {
        detailsFragment = MovieDetailsActivityFragment.newInstance(movie, transitionName);
        android.app.FragmentTransaction ft = getFragmentManager().beginTransaction();
        ft.replace(R.id.movie_detail_container, detailsFragment);
        ft.commit();
    }
}

[Buggy Hunk]
detailsFragment = MovieDetailsActivityFragment.newInstance(movie,transitionName);

[Patch]
detailsFragment = MovieDetailsActivityFragment.newInstance(movie,transitionName,true);

[Demonstration 3]

[Buggy Method]
@Override
public void onBackPressed() {
    if (loginSignin.getVisibility() == View.VISIBLE) {
        phoneEditText.setText("");
        passwordEditText.setText("");
        loginSignin.setVisibility(View.GONE);
        loginStartup.setVisibility(View.VISIBLE);
    } else if (loginLostCode.getVisibility() == View.VISIBLE) {
        lostCodePhone.setText("");
        loginLostCode.setVisibility(View.GONE);
        loginSignin.setVisibility(View.VISIBLE);
        showKeyboard(phoneEditText);
    } else if (loginTutorial.getVisibility() == View.VISIBLE) {
        loginTutorial.setVisibility(View.GONE);
        loginWelcome.setVisibility(View.VISIBLE);
    } else if (loginWelcome.getVisibility() == View.VISIBLE) {
        loginWelcome.setVisibility(View.GONE);
        loginSignin.setVisibility(View.VISIBLE);
    } else if (loginNameView.getVisibility() == View.VISIBLE) {
        loginNameView.setVisibility(View.GONE);
        loginTutorial.setVisibility(View.VISIBLE);
    } else if (loginNewsletter.getVisibility() == View.VISIBLE && previousView != null) {
        newsletterEmail.setText("");
        loginNewsletter.setVisibility(View.GONE);
        previousView.setVisibility(View.VISIBLE);
        if (previousView == loginSignin) {
            showKeyboard(phoneEditText);
        }
    } else if (loginVerifyCode.getVisibility() == View.VISIBLE) {
        showLostCodeScreen();
    } else {
        super.onBackPressed();
    }
}

[Buggy Hunk]
loginTutorial.setVisibility(View.VISIBLE);

[Patch]
loginWelcome.setVisibility(View.VISIBLE);