Java

package penugasan;
public class DataAccesObject {
    private Database dataBase;
    private long currentFalcutyID;
    private String currentFalcutyName;
    private long currentStudentID;
    private String currentStudentName;
    public String string;
    public String name;



    public DataAccesObject() {
        this.dataBase = new Database();
    }

    public boolean deleteFaculty(Long ID){
        final Faculty[] faculty = this.dataBase.getFaculty();
        for (int i = 0; i < faculty.length; ++i) {
            if (faculty[i] != null && faculty[i].getID().equals(ID)) {
                faculty[i] = null;
                return true;
            }
        }
        return false;
    }

    public boolean createFaculty(Long ID, String name){
        final Faculty faculty = new Faculty(ID, name);
        this.currentFalcutyID = ID;
        this.currentFalcutyName = name;
        final Faculty[] faculty2 = this.dataBase.getFaculty();
        if (faculty2[ID.intValue()] == null) {
            faculty2[ID.intValue()] = faculty;
            return true;
        }
        return false;

    }
   
    //convert value to string and pass it as paramater to showFaculty in facultyView
    public String readFaculties(){
        String string = "";
        final Faculty[] faculty = this.dataBase.getFaculty();
        for (int i = 0; i < faculty.length; ++i) {
            if (faculty[i] != null) {
                string = string + faculty[i].getID() + " " + faculty[i].getName() + "\n";
            }
        }
        //this.string = string;
        return string;
    }

    //find faculty by input name
    public Faculty readFacultyByName(String name){
        final Faculty[] faculty = this.dataBase.getFaculty();
        for (int i = 0; i < faculty.length; ++i) {
            if (faculty[i] != null && faculty[i].getName().equals(name)) {
                return faculty[i];
            }
        }
        return null;
    }
}

package penugasan;

import java.util.Scanner;

public class FacultyView {
    private DataAccesObject dao;
    public String name;
    public FacultyView(DataAccesObject dao) {
        this.dao = dao;
    }
		
    public void start() {
    	// cant grab the string value from readFaculties
        this.showFaculty(this.dao.readFaculties());
        System.out.println("Faculty View Menu : ");
        System.out.println("1 Create Faculty");
        System.out.println("2 Delete Faculty");
        System.out.println("3 Main Menu");
        System.out.print("Input your choice : ");
        final String nextLine = new Scanner(System.in).nextLine();
        if (nextLine.equals("1")) {
            this.createFaculty();
        }
        else if (nextLine.equals("2")) {
            this.deleteFaculty();
        }
        else {
            if (nextLine.equals("3")) {
                return;
            }
            System.out.println("Unrecognize Menu\n\n");
            this.start();
        }
    }


    //print the string
    public void showFaculty(final String name) {
        System.out.println("\n\nList Of Faculty : ");
        System.out.println(name);
    }

    public void createFaculty() {
        System.out.print("\nInput ID : ");
        final String nextLine = new Scanner(System.in).nextLine();
        System.out.print("Input Name : ");
        final String nextName = new Scanner(System.in).nextLine();
        this.dao.createFaculty(Long.parseLong(nextLine), nextName);
        this.start();
    }

    public void deleteFaculty() {
        System.out.print("\nInput ID : ");
        this.dao.deleteFaculty(Long.parseLong(new Scanner(System.in).nextLine()));
        this.start();
    }
}

package penugasan;
public class Database{
    private Faculty[] faculties;


    public Database() {
        Faculty faculty = new Faculty();
    }

    public Faculty[] getFaculty() {

        //Long facultyID = super.getCurrentFalcutyID();
        //String facultyName = super.getCurrentFalcutyName();

        this.faculties = new Faculty[10];
        return faculties;
    }
}

package penugasan;

import java.util.Scanner;

/// Main class
public class Test {
    public static void main(String[] args) {
        DataAccesObject dao = new DataAccesObject();
        FacultyView facultyView = new FacultyView(dao);
        StudentView studentView = new StudentView(dao);

        while(true){
            System.out.println("\nMain Menu : ");
            System.out.println("1. Student");
            System.out.println("2. Faculty");
            System.out.println("3. Exit");
            System.out.println("Input your choice : ");

            Scanner scanner = new Scanner(System.in);
            String choice = scanner.nextLine();
            if (choice.equals("1")){
                studentView.start();
            }else if (choice.equals("2")){
                facultyView.start();
            }else if(choice.equals("3")){
                System.exit(0);
            }else {
                System.out.println("Wrong Choice");
            }
        }
    }
}

Hi guys, 
I know how to write code in Java (basic and intermediate level). However, I have very little experience in looking at other peoples' code (experts) and understanding those. I know this is very much required in the industry. I would like to understand how architectures, e.g. MVC and design patterns are implemented by experts. 

Therefore, I am asking your recommendations for existing GITHUB projects for learning. I would like to look at a project with the following properties:

1.	Built with CORE java. It should have some sort of GUI (maybe JavaFX, which I know isn't CORE java).
2.	Followed some architecture and design patterns.
3.	It can be a game for example.
4.	It should have at least some documentation.

I have searched GUTHUB projects and too much choice has overwhelmed me. Please provide your valuable suggestion so that I can at least start somewhere.

Bye.   

I wanna create a library for sending notification to my android app but i don't know how it works and what kind of data i should give to the function in the class. this is my code for sending notification but i don't know how to put it in the class for using in another sections of the app. This code works in MainActivity

Intent intent = new Intent(context, MainActivity.class);
               PendingIntent contentIntent = PendingIntent.getActivity(context, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);

               NotificationCompat.Builder b = new NotificationCompat.Builder(context);

               b.setAutoCancel(true)
                       .setDefaults(Notification.DEFAULT_ALL)
                       .setWhen(System.currentTimeMillis())
                       .setSmallIcon(R.drawable.ic_launcher_background)
                       .setTicker("Hearty365")
                       .setContentTitle("Default notification")
                       .setContentText("Lorem ipsum dolor sit amet, consectetur adipiscing elit.")
                       .setDefaults(Notification.DEFAULT_LIGHTS | Notification.DEFAULT_SOUND)
                       .setContentIntent(contentIntent)
                       .setContentInfo("Info");


               NotificationManager notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
               notificationManager.notify(1, b.build());

import java.io.IOException;
import java.net.URL;
import java.net.HttpURLConnection;
import java.lang.ClassNotFoundException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public final class TomSampleServletClient extends HttpServlet {
    
    @Override
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
        xxxx;
        xxxx;
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
    <servlet>
       <servlet-name>TomSampleServletClient</servlet-name>
       <servlet-class>TomSampleServletClient</servlet-class>
    </servlet>
    <servlet-mapping>
       <servlet-name>TomSampleServletClient</servlet-name>
       <url-pattern>/TomSampleServletClient</url-pattern>
    </servlet-mapping>
</web-app>