Introduction to Java and features of java and execution flow

Java is a high-level, object-oriented programming language developed by James Gosling at Sun Microsystems (now owned by Oracle) and released in 1995. It is designed to be platform-independent, meaning programs written in Java can run on any system that has a Java Virtual Machine (JVM).

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Key Features of Java

1. Platform Independence

   • Java follows the "Write Once, Run Anywhere" (WORA) principle.
   • Code is compiled into bytecode, which runs on the JVM, making it cross-platform.

2. Object-Oriented Programming (OOP)

   • Java is based on OOP concepts like Encapsulation, Inheritance, Polymorphism, and Abstraction.

3. Simple and Secure

   • Java eliminates complex features of C++ (e.g., pointers).
   • It has a built-in security model and automatic memory management (Garbage Collection).

4. Robust and Reliable

   • Java has strong memory management and exception handling to prevent crashes.

5. Multi-threading Support

   • Java allows concurrent execution of multiple tasks, improving performance.

6. Rich API and Libraries

   • Java provides a wide range of built-in libraries for networking, database handling, and GUI development.

7. Community and Industry Support

   • Java is widely used in enterprise applications, mobile development (Android), web applications, and cloud computing.

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Java Program Execution Flow

1. Write Java Code (.java file)
2. Compile using javac (Java Compiler) → Converts code to bytecode (.class file)
3. Execute using JVM → Runs bytecode on any platform with a Java Runtime Environment (JRE)

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Basic Java Program

java

public class HelloWorld {
    public static void main(String[] args) {
        System.out.println("Hello, World!");
    }
}

Explanation:

• public class HelloWorld → Defines a class named HelloWorld.
• public static void main(String[] args) → The main method, entry point of Java programs.
• System.out.println("Hello, World!"); → Prints text to the console.

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Applications of Java

• Web Development (Spring, Hibernate)
• Mobile Development (Android)
• Enterprise Applications (Banking, Finance)
• Game Development
• Cloud Computing & Big Data

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