Object Oriented Programming Using JAVA

  The Problem Before Java In the early days of programming, developers faced a big issue: portability . Every programming language required code to be rewritten for different operating systems. A program written for Windows wouldn’t run on Linux or Mac without modifications. Imagine you are a Bollywood director making a movie. If you shoot in Hindi, it won’t reach a Tamil-speaking audience unless you dub or remake it. This was the same problem in software—each platform needed a different version of the same program. The Birth of Java & JVM (1991-1995) In 1991, James Gosling and his team at Sun Microsystems wanted to solve this problem. They dreamed of a language that could run anywhere, on any device, without modification . They created Java , but Java alone wasn’t enough. They needed a translator that could understand Java and speak the language of any operating system. This is where the Java Virtual Machine (JVM) was born. Java Compiles Code to Bytecode : Instead of com...

Let me take you on a journey through time. Imagine you are in the early days of computing, where machines were big, and programmers were pioneers. The world of programming was starting to take shape, and over time, languages evolved to make things easier, faster, and more powerful. And one of the most popular and influential languages today is Java , but it didn't come out of nowhere. 1. The Beginning: FORTRAN (1950s) In the late 1950s, computing was a daunting task. The first major programming language to be developed was FORTRAN (short for Formula Translation ), invented by IBM in 1957. It was designed to make scientific and engineering calculations faster and more efficient. FORTRAN helped move programming from machine-level code to something more human-readable. It was like giving humans the ability to talk to computers more easily. Key Contribution : First high-level language, allowing scientists to do complex calculations without knowing machine code. 2. COBOL: The Business...

  Computer architecture refers to the design and structure of a computer system. There are several types of computer architectures, each designed for specific purposes. Here are the main ones explained in simple terms: 1. Von Neumann Architecture (Stored Program Architecture) Description : This is the most common architecture for general-purpose computers. It consists of a Central Processing Unit (CPU) , memory , and input/output devices . How it works : In Von Neumann architecture, both data and instructions (programs) are stored in the same memory. The CPU fetches instructions from memory, executes them, and then moves to the next instruction. This architecture is simple and easy to implement. Example : Most personal computers, laptops, and desktops use this architecture. 2. Harvard Architecture Description : Harvard architecture is similar to Von Neumann, but with a key difference: it has separate memory for data and instructions . This allows the CPU to fetch instructions a...

The `@Override` annotation is used in Java to indicate that a method in a subclass is overriding a method with the same signature in its superclass. It is not mandatory to use `@Override`, but it helps in detecting errors during compilation if the method signature does not match any method in the superclass. Here are some key points about `@Override`: 1. Purpose: It provides compile-time checking that a method is indeed overriding a method from a superclass. If there is a mismatch in the method signature (e.g., misspelling of method name, incorrect parameters), the compiler will generate an error. 2. Usage: `@Override` is placed immediately before the method declaration in the subclass that is intended to override a method in the superclass. 3. Compatibility: `@Override` annotation was introduced in Java 5. It can only be used with methods that are overriding a superclass method. If a method is not overriding a superclass method, using `@Override` will result in a compilation error....

Getter and setter methods, also known as accessor and mutator methods, are used to retrieve and modify the values of private variables (fields) in a class. They provide controlled access to the class attributes, allowing encapsulation and maintaining data integrity. Here's an example demonstrating getter and setter methods in Java: public class Person {     private String name;     private int age;     // Getter method for the name attribute     public String getName() {         return name;     }     // Setter method for the name attribute     public void setName(String name) {         this.name = name;     }     // Getter method for the age attribute     public int getAge() {         return age;     }     // Setter method for the age attribute     public void setAge(int age) {       ...

The Java Virtual Machine (JVM) relies on the Just-In-Time (JIT) compilation to improve the runtime performance of Java programs. However, theoretically, it is possible to run Java programs without JIT compilation. In practice, running Java programs without JIT compilation is not a common scenario, and it would impact the performance of the Java applications. Here's how it works: Without JIT Compilation: In the absence of JIT compilation, the JVM would interpret the bytecode directly. Interpretation involves reading the bytecode line by line and executing the corresponding native instructions. This approach tends to be slower compared to executing native machine code directly. With JIT Compilation: JIT compilation converts bytecode into native machine code just before execution. The generated native machine code is specific to the underlying hardware. This allows the program to execute more efficiently, as it is no longer interpreted line by line. Advantages of JIT Compilation: Impr...

 The Java compilation process involves several steps, known as the Java compilation and execution lifecycle. Here's an overview: 1. Writing Java Source Code (HelloWorld.java): // HelloWorld.java public class HelloWorld {     public static void main(String[] args) {         System.out.println("Hello, World!");     } } Programmers write Java code using a text editor or an integrated development environment (IDE). The code is typically saved in a file with a .java extension. This file contains the human-readable Java source code. 2. Compilation (Java Compiler - javac): $ javac HelloWorld.java The Java source code is compiled by the Java Compiler (javac). During compilation, the compiler performs several tasks: Syntax Checking: Ensures that the code follows the correct syntax defined by the Java language. Semantic Analysis: Checks for semantic errors, ensuring that the code makes sense in the context of the Java language. Bytecode Generation: ...

The compilation process of a C program involves several stages, from the source code written in the hello.c file to the creation of an executable file that can be loaded and executed by the operating system. Here is a simplified overview of the compilation process: Source Code (hello.c): The process begins with a programmer writing the source code in the C programming language. The source code is usually saved in a file with a .c extension, such as hello.c. Preprocessing: The preprocessor (cpp) is the first stage of compilation. It handles directives, such as #include and #define, and expands them. The result is a modified version of the source code, often referred to as the "preprocessed code." Compilation: The compiler (gcc) takes the preprocessed code and translates it into assembly code specific to the target platform. The output is stored in an assembly code file. Assembly: The assembler (as) takes the assembly code and converts it into machine code in the form of reloca...

The history of computer programming languages is a fascinating journey that spans several decades. Here's a brief overview of key milestones in the evolution of programming languages: 1. Machine Code and Assembly Language (1940s): In the early days of computing, programmers worked directly with machine code, the binary language understood by computers. Assembly language, a low-level programming language using mnemonic codes, was introduced to make programming more human-readable. 2. Fortran (1957): Developed by IBM, Fortran (short for Formula Translation) was the first high-level programming language. Designed for scientific and engineering calculations, Fortran introduced the concept of a compiler, translating high-level code into machine code. 3. Lisp (1958): Developed by John McCarthy, Lisp (short for List Processing) was one of the earliest high-level languages designed for symbolic reasoning and artificial intelligence research. Known for its unique approach to code as data an...