[Demonstration 1]

[Buggy Method]
public static void showAddFragmentSlideDown(Activity activity, Fragment fragment, String backStack) {
    if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.LOLLIPOP_MR1) {
        fragment.setEnterTransition(new Slide(Gravity.BOTTOM).setDuration(200));
        activity.getFragmentManager().beginTransaction().add(R.id.activity_main_vg_fragment, fragment).addToBackStack(backStack).commit();
    } else {
        activity.getFragmentManager().beginTransaction().add(R.id.activity_main_vg_fragment, fragment, fragment.getClass().getSimpleName()).setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE).addToBackStack(backStack).commit();
    }
}

[Buggy Hunk]
.add(R.id.activity_main_vg_fragment, fragment, fragment.getClass().getSimpleName())

[Patch]
.replace(R.id.activity_main_vg_fragment, fragment, fragment.getClass().getSimpleName())

[Demonstration 2]

[Buggy Method]
private void open_events() {
    coutureib.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            Fragment fragment = new Couture();
            FragmentTransaction ft = getFragmentManager().beginTransaction();
            ft.replace(R.id.content_frame, fragment);
            ft.commit();
        }
    });
    mrMrsExodia.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            Fragment fragment = new Couture();
            FragmentTransaction ft = getFragmentManager().beginTransaction();
            ft.replace(R.id.content_frame, fragment);
            ft.commit();
        }
    });
}

[Buggy Hunk]
Fragment fragment = new Couture();

[Patch]
Fragment fragment = new MrMrsExodia();

[Demonstration 3]

[Buggy Method]
private void applyOnlineStatus(final MyViewHolder holder, ChatListModel chatListModel) {
    DatabaseReference dbOnlineStatus = DBREF.child("Usersessions").child(chatListModel.getUserkey()).child("online").getRef();
    ValueEventListener valueEventListener = dbOnlineStatus.addValueEventListener(new ValueEventListener() {

        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            if (dataSnapshot.exists()) {
                boolean online = dataSnapshot.getValue(Boolean.class);
                if (online == true) {
                    holder.onlineStatus.setVisibility(View.VISIBLE);
                } else {
                    holder.onlineStatus.setVisibility(View.GONE);
                }
            }
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {
        }
    });
    hashMapVLE.put(dbOnlineStatus, valueEventListener);
}

[Buggy Hunk]
DatabaseReference dbOnlineStatus = DBREF.child("Usersessions").child(chatListModel.getUserkey()).child("online").getRef();

[Patch]
DatabaseReference dbOnlineStatus = DBREF.child("Users").child("Usersessions").child(chatListModel.getUserkey()).child("online").getRef();