Complete Core Java Programming Textbook & Guide

☕ Java Course Table of Contents

1. Introduction & JVM Architecture 2. Data Types & Primitive Ranges 3. OOP Pillars (Inheritance, Polymorphism) 4. Abstract Classes & Interfaces 5. Exception Handling Mechanism 6. Java Collections Framework 7. Multithreading & Concurrency 8. File I/O & Character Streams 9. Database Connectivity (JDBC) 10. Student Practice Lab Exercises

1. Introduction & JVM Architecture

Java was created by James Gosling and his team at Sun Microsystems in 1995 (now Oracle Corporation). It was designed around the paradigm of "Write Once, Run Anywhere" (WORA). Java code is compiled into platform-independent bytecode (.class files), which is executed by the Java Virtual Machine (JVM).

Component	Full Name	Role & Purpose
JDK	Java Development Kit	Includes compiler (`javac`), debugger, tools, and JRE required to develop Java applications.
JRE	Java Runtime Environment	Contains libraries (`rt.jar`) and JVM required to execute compiled Java bytecodes.
JVM	Java Virtual Machine	Abstract computing machine that interprets bytecode into native machine code.

2. Data Types & Primitive Ranges

Data Type	Size	Default Value	Range / Description
`byte`	1 byte	0	-128 to 127
`short`	2 bytes	0	-32,768 to 32,767
`int`	4 bytes	0	-2,147,483,648 to 2,147,483,647
`long`	8 bytes	0L	-9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
`float`	4 bytes	0.0f	Up to 7 decimal digits precision
`double`	8 bytes	0.0d	Up to 15 decimal digits precision
`char`	2 bytes	'\u0000'	Unicode 0 to 65,535
`boolean`	1 bit (logical)	false	true or false

3. OOP Pillars (Inheritance & Polymorphism)

Java OOP Demonstration

class Course {
    protected String courseName;

    public Course(String name) {
        this.courseName = name;
    }

    public void displayInfo() {
        System.out.println("Enrolled in Course: " + courseName);
    }
}

class JavaCourse extends Course {
    private int durationDays;

    public JavaCourse(String name, int duration) {
        super(name);
        this.durationDays = duration;
    }

    @Override
    public void displayInfo() {
        System.out.println("KKCC Java Track: " + courseName + " | Duration: " + durationDays + " Days");
    }
}

public class Main {
    public static void main(String[] args) {
        Course c = new JavaCourse("Core Java & OOPs", 90);
        c.displayInfo();
    }
}

4. Abstract Classes & Interfaces

Java Interface Example

interface StudentPortal {
    void login(String username, String password);
    void viewQuizzes();
}

class KKCCStudentPortal implements StudentPortal {
    public void login(String user, String pass) {
        System.out.println("User " + user + " logged into telugututorial.in portal!");
    }
    public void viewQuizzes() {
        System.out.println("Displaying available Java quizzes...");
    }
}

5. Exception Handling Mechanism

Try-Catch-Finally

public class ExceptionDemo {
    public static void main(String[] args) {
        try {
            int a = 10, b = 0;
            int result = a / b;
        } catch (ArithmeticException e) {
            System.err.println("Error: Division by zero caught!");
        } finally {
            System.out.println("Cleanup tasks executed in finally block.");
        }
    }
}

6. Java Collections Framework

ArrayList & HashMap

import java.util.*;

public class CollectionExample {
    public static void main(String[] args) {
        Map<Integer, String> studentMap = new HashMap<>();
        studentMap.put(101, "Srinivas K.");
        studentMap.put(102, "Meena T.");

        for (Map.Entry<Integer, String> entry : studentMap.entrySet()) {
            System.out.println("ID: " + entry.getKey() + " | Name: " + entry.getValue());
        }
    }
}

7. Multithreading & Concurrency

Runnable Thread

class LabTask implements Runnable {
    public void run() {
        System.out.println("Background thread running in KKCC Java Lab...");
    }
}

public class ThreadMain {
    public static void main(String[] args) {
        Thread t1 = new Thread(new LabTask());
        t1.start();
    }
}

9. Database Connectivity (JDBC)

JDBC PreparedStatement Example

import java.sql.*;

public class JDBCDemo {
    public static void main(String[] args) {
        String url = "jdbc:mysql://localhost:3306/kkcc_db";
        String user = "root", pass = "secret";

        try (Connection conn = DriverManager.getConnection(url, user, pass)) {
            String sql = "SELECT * FROM students WHERE course = ?";
            PreparedStatement pstmt = conn.prepareStatement(sql);
            pstmt.setString(1, "Java");
            ResultSet rs = pstmt.executeQuery();

            while (rs.next()) {
                System.out.println("Student: " + rs.getString("name"));
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

📝 Core Java Student Exercises & Homework

Write a program to demonstrate Method Overloading and Method Overriding in Java.
Create a custom exception class InvalidAgeException and throw it when age < 18.
Write a program to read student records from a MySQL table using JDBC PreparedStatement.
Create a multi-threaded program using Runnable interface to calculate factorial in parallel.

Core Java Programming Complete Manual