Computer Fundamentals and Java Programming

Study Notes

A computer is a versatile machine capable of performing various tasks, from simple mathematical operations to complex multimedia animations.
Computers need instructions—programs—to operate.
Programs are translated into machine code (Object Code) by a translator (interpreter or compiler).
Source Code is the human-readable form of a program.
A programmer is a person who creates programs.
Modern applications require global outlook, often employing cross-platform, machine-independent languages like Java.

Java is a machine-independent programming language suitable for internet-based applications.
Java programs run on any platform.
BlueJ is an integrated development environment (IDE) that facilitates interactive Java programming for beginners.

OOP is a programming style where programs are organized around objects.
Objects have state (characteristics) and behavior (functions).
Objects consist of real-world entities or items (living or non-living).
OOP involves separating a program into self-contained objects, facilitating reuse of components.

Objects are real-world entities with characteristics, called state, and actions, called behavior.
Examples of objects: a car, a pen, a dog, a building.

A class is a blueprint or a template for creating objects.
A class defines common characteristics (state) and actions (behavior) that objects share.
A class acts like a factory for producing similar objects, and similar objects are instances of a certain class.

Abstraction isolates complex internal implementation details from users.
Users only see the essential features.
Example: Using an ATM—users interact with the interface, not the internal workings.

Encapsulation bundles data (state) and code (behavior) into a single unit, called an object.
This prevents unauthorized access to data, providing data security.
Objects expose only essential components to external users.

Inheritance allows new classes to inherit properties and methods of existing classes.
This promotes reusable code and reduces redundancy.
Derived classes can add additional properties and methods as needed.

Comments are ignored by the computer and explain code sections.
Reserved words (keywords) have specific meanings, like class, public, static, void, etc.
Classes define object types.
Main method is where program execution begins.
Arguments are passed to classes or methods to interact.
Keyword static indicates a method or variable belonging to the class rather than a specific object instance.

Variables are named memory locations that store data.
Data types define what kind of data a variable can hold.
Common data types: integers (int), floating-point numbers (float, double), characters (char), Boolean values (boolean).